Film for flip chip type semiconductor back surface

ABSTRACT

The present invention provides a film for flip chip type semiconductor back surface, which is to be formed on a back surface of a semiconductor element flip-chip connected on an adherend, the film including a wafer adhesion layer and a laser marking layer, in which the wafer adhesion layer has an elastic modulus (at 50° C.) of 10 MPa or less and the laser marking layer has an elastic modulus (at 50° C.) of 100 MPa or more.

FIELD OF THE INVENTION

The present invention relates to a film for flip chip type semiconductorback surface. A film for flip chip type semiconductor back surface isused for protecting a back surface of a chip-shaped workpiece (such as asemiconductor chip) and enhancing strength. Moreover, the inventionrelates to a semiconductor device using the dicing tape-integrated filmfor semiconductor back surface having the film for flip chip typesemiconductor back surface and a process for producing the device.

BACKGROUND OF THE INVENTION

Recently, thinning and miniaturization of a semiconductor device and itspackage have been increasingly demanded. Therefore, as the semiconductordevice and its package, those in which a semiconductor chip (chip-shapedworkpiece) is fixed to a substrate in a form where a circuit face of thesemiconductor chip is opposed to an electrode-formed face of thesubstrate (i.e., semiconductor chip produced by flip chip bonding, or aflip chip-mounted semiconductor device) have been widely utilized. Insuch a semiconductor device or the like, the back surface of thesemiconductor chip (chip-shaped workpiece) is protected with aprotective film to inhibit the damage of the semiconductor chip in somecases (see, for example, Patent Documents 1 to 10).

-   Patent Document 1: JP-A-2008-166451-   Patent Document 2: JP-A-2008-006386-   Patent Document 3: JP-A-2007-261035-   Patent Document 4: JP-A-2007-250970-   Patent Document 5: JP-A-2007-158026-   Patent Document 6: JP-A-2004-221169-   Patent Document 7: JP-A-2004-214288-   Patent Document 8: JP-A-2004-142430-   Patent Document 9: JP-A-2004-072108-   Patent Document 10: JP-A-2004-063551

SUMMARY OF THE INVENTION

However, in the production of a semiconductor device, there is desired aback surface protective film for protecting the back surface of asemiconductor chip, which is capable of exhibiting an excellent holdingforce in the dicing step of a semiconductor wafer, capable of peelingthe semiconductor chip formed by dicing from a base material with anexcellent picking-up property together with the film for flip chip typesemiconductor back surface in the picking-up step after the dicing step,and capable of suppressing or preventing the attachment of thesemiconductor chip to a support through the film for flip chip typesemiconductor back surface after the picking-up step even when thesemiconductor chip whose back surface is protected with the film forflip chip type semiconductor back surface is placed on the support.

Moreover, the attachment of a back surface protective film forprotecting a back surface of a semiconductor chip to the back surface ofa semiconductor chip obtained by dicing a semiconductor wafer in adicing step results in the addition of a step for the attachment, sothat the number of steps increases and cost and the like increase.Furthermore, owing to the thinning in recent years, the semiconductorchip may be damaged in some cases in a picking-up step of thesemiconductor chip after the dicing step. Thus, it is desired toreinforce the semiconductor wafer or semiconductor chip until thepicking-up step.

The present invention has been devised in consideration of the foregoingproblem and an object thereof is to provide a film for flip chip typesemiconductor back surface capable of exhibiting an excellent holdingforce in the dicing step of the semiconductor wafer, capable of peelingthe semiconductor chip formed by dicing from a base material with anexcellent picking-up property together with the film for flip chip typesemiconductor back surface in the picking-up step after the dicing step,and capable of suppressing or preventing the attachment of thesemiconductor chip to a support through the film for flip chip typesemiconductor back surface after the picking-up step even when thesemiconductor chip whose back surface is protected with the film forflip chip type semiconductor back surface is placed on the support,Moreover, an object thereof is to provide a dicing tape-integrated filmfor flip chip type semiconductor back surface capable of being utilizedfrom the dicing step of the semiconductor wafer to the flip chip bondingstep of the semiconductor chip. Furthermore, another object of theinvention is to provide a dicing tape-integrated film for flip chip typesemiconductor back surface capable of exhibiting an excellent holdingforce in the dicing step of the semiconductor wafer, capable of peelingthe semiconductor chip formed by dicing from a base material with anexcellent picking-up property together with the film for flip chip typesemiconductor back surface in the picking-up step after the dicing step,and capable of suppressing or preventing the attachment of thesemiconductor chip to a support through the film for flip chip typesemiconductor back surface after the picking-up step even when thesemiconductor chip whose back surface is protected with the film forflip chip type semiconductor back surface is placed on the support aswell as capable of exhibiting an excellent laser marking property and anappearance property after the flip chip bonding step of thesemiconductor chip.

MEANS FOR SOLVING THE PROBLEMS

As a result of intensive investigations for solving the above-mentionedconventional problems, the present inventors have found that, when afilm for flip chip type semiconductor back surface having a multilayeredstructure including layers each having a specific elastic modulus islaminated on a pressure-sensitive adhesive layer of a dicing tape havinga base material and the pressure-sensitive adhesive layer to form thedicing tape and the film for flip chip type semiconductor back surfacein an integrated fashion, the laminate (dicing tape-integrated film forsemiconductor back surface) where the dicing tape and the film for flipchip type semiconductor back surface are formed in an integrated fashioncan be utilized from the dicing step of the semiconductor wafer to theflip chip bonding step of the semiconductor chip as well as an excellentholding force can be exhibited in the dicing step of the semiconductorwafer, the semiconductor chip formed by dicing can be peeled from thepressure-sensitive adhesive layer of the dicing tape with an excellentpicking-up property together with the film for flip chip typesemiconductor back surface in the picking-up step after the dicing step,also the attachment of the semiconductor chip to a support through thefilm for flip chip type semiconductor back surface can be suppressed orprevented after the picking-up step even when the semiconductor chipwhose back surface is protected with the film for flip chip typesemiconductor back surface is placed on the support, and further anexcellent laser marking property and an excellent appearance propertycan be exhibited after the flip chip bonding step of the semiconductorchip, thereby accomplishing the invention.

Namely, the present invention provides a film for flip chip typesemiconductor back surface, which is to be formed on a back surface of asemiconductor element flip-chip connected on an adherend,

wherein said film comprises a wafer adhesion layer and a laser markinglayer, and

wherein the wafer adhesion layer has an elastic modulus (at 50° C.) of10 MPa or less and the laser marking layer has an elastic modulus (at50° C.) of 100 MPa or more.

Furthermore, the invention provides a dicing tape-integrated film forsemiconductor back surface, comprising:

a dicing tape comprising a base material and a pressure-sensitiveadhesive layer formed on the base material; and

the film for flip chip type semiconductor back surface having theabove-mentioned constitution and properties, which is formed on thepressure-sensitive adhesive layer of the dicing tape in such a mannerthat the laser marking layer is laminated on the pressure-sensitiveadhesive layer of the dicing tape.

As above, the dicing tape-integrated film for semiconductor back surfaceaccording to the invention is formed in a form where the film for flipchip type semiconductor back surface is integrated with the dicing tapeincluding the base material and the pressure-sensitive adhesive layer,and the film for flip chip type semiconductor back surface has amultilayered structure including a wafer adhesion layer and a lasermarking layer and the wafer adhesion layer and the laser marking layereach have a specific elastic modulus. Therefore, by attaching the dicingtape-integrated film for semiconductor back surface onto a workpiece(semiconductor wafer) utilizing the wafer adhesion layer with anexcellent close adhesiveness at dicing a wafer (semiconductor wafer),the workpiece can be effectively diced while being held. Also, after theworkpiece is diced to form a chip-shaped workpiece (semiconductor chip),by peeling the chip-shaped workpiece from the pressure-sensitiveadhesive layer of the dicing tape together with the film for flip chiptype semiconductor back surface, the back surface-protected chip-shapedworkpiece can be easily obtained. In addition, since the chip-shapedworkpiece has a wafer adhesion layer having a specific elastic modulusand a laser marking layer having a specific elastic modulus, theattachment of the semiconductor chip to a support through the film forflip chip type semiconductor back surface can be suppressed or preventedafter the picking-up step even when the semiconductor chip whose backsurface is protected with the film for flip chip type semiconductor backsurface is placed on the support. Furthermore, since the laser markinglayer becomes the outermost layer on the back surface of the chip-shapedworkpiece, laser marking can be performed on the back surface (i.e., thelaser marking layer) of the chip-shaped workpiece with an excellentlaser marking property. Also, an appearance property and the like can beeffectively enhanced.

Furthermore, in the dicing tape-integrated film for semiconductor backsurface of the invention, since the dicing tape and the film for flipchip type semiconductor back surface are formed in an integrated fashionas mentioned above, the film for flip chip type semiconductor backsurface can also be attached at the time when the dicing tape isattached to the back surface of the semiconductor wafer before thedicing step and thus a step of attaching the film for flip chip typesemiconductor back surface alone (film for flip chip type semiconductorback surface-attaching step) is not necessary. In addition, in thesubsequent dicing step and picking-up step, since the film for flip chiptype semiconductor back surface is attached on the back surface of thesemiconductor wafer or the back surface of the semiconductor chip formedby dicing, the semiconductor wafer or the semiconductor chip can beeffectively protected and thus the damage of the semiconductor chip canbe suppressed or prevented in the dicing step or subsequent steps(picking-up step, etc.).

In the invention, the wafer adhesion layer and the laser marking layerare preferably both colored. When the film for flip chip typesemiconductor back surface is colored, not only a laser marking propertyis improved but also the dicing tape and the film for flip chip typesemiconductor back surface can be easily distinguished from each other,so that workability and the like can be enhanced.

The dicing tape-integrated film for semiconductor back surface accordingto the invention can be suitably used for a flip chip-mountedsemiconductor device.

The present invention also provides a process for producing asemiconductor device, the process comprising:

attaching a workpiece onto a wafer adhesion layer in the film for flipchip type semiconductor back surface of the above-mentioned dicingtape-integrated film for semiconductor back surface,

dicing the workpiece to form a chip-shaped workpiece,

peeling the chip-shaped workpiece from the pressure-sensitive adhesivelayer of the dicing tape together with the film for flip chip typesemiconductor back surface, and

fixing the chip-shaped workpiece to an adherend by flip chip bonding.

In addition, the invention further provides a flip chip-mountedsemiconductor device, which is manufactured using the above-mentioneddicing tape-integrated film for semiconductor back surface, thesemiconductor device comprising a chip-shaped workpiece and the film forflip chip type semiconductor back surface attached to a back surface ofthe chip-shaped workpiece.

The film for flip chip type semiconductor back surface according to theinvention can suppress or prevent the attachment of the semiconductorchip to a support. Moreover, since a dicing tape and a film for flipchip type semiconductor back surface are formed in an integrated fashionas well as the film for flip chip type semiconductor back surface has amultilayered structure containing a wafer adhesion layer having aspecific elastic modulus and a laser marking layer having a specificelastic modulus, the dicing tape-integrated film for semiconductor backsurface according to the invention can be utilized from the dicing stepof the semiconductor wafer to the flip chip bonding step of thesemiconductor chip. Specifically, the dicing tape-integrated film forsemiconductor back surface according to the invention can exhibit anexcellent holding force in the dicing step of the semiconductor wafer,the semiconductor chip formed by dicing can be peeled from thepressure-sensitive adhesive layer of the dicing tape with an excellentpicking-up property together with the film for flip chip typesemiconductor back surface in the picking-up step after the dicing step,and the attachment of the semiconductor chip to a support through thefilm for flip chip type semiconductor back surface can be suppressed orprevented after the picking-up step even when the semiconductor chipwhose back surface is protected with the film for flip chip typesemiconductor back surface is placed on the support, as well as anexcellent laser marking property and an excellent appearance propertycan be exhibited after the flip chip bonding step of the semiconductorchip. Moreover, in the flip chip bonding step and the like, since theback surface of the semiconductor chip is protected with the film forflip chip type semiconductor back surface, breakage, chipping, warp, andthe like of the semiconductor chip can be effectively suppressed orprevented. Needless to say, the dicing tape-integrated film forsemiconductor back surface according to the invention can effectivelyexhibit functions thereof in steps other than the steps from the dicingstep to the flip chip bonding step of the semiconductor chip.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional schematic view showing one embodiment of adicing tape-integrated film for semiconductor back surface according tothe invention.

FIGS. 2A to 2D are cross-sectional schematic views showing oneembodiment of a process for producing a semiconductor device using adicing tape-integrated film for semiconductor back surface according tothe invention.

DESCRIPTION OF REFERENCE NUMERALS AND SIGNS

-   -   1 dicing tape-integrated film for semiconductor back surface    -   2 film for flip chip type semiconductor back surface    -   21 laser marking layer    -   22 wafer adhesion layer    -   3 dicing tape    -   31 base material    -   32 pressure-sensitive adhesive layer    -   4 semiconductor wafer (workpiece)    -   5 semiconductor chip (chip-shaped workpiece)    -   51 bump formed at circuit face of semiconductor chip 5    -   6 adherend    -   61 conductive material for conjunction adhered to connecting pad        of adherend 6

DETAILED DESCRIPTION OF THE INVENTION

An embodiment of the present invention is described with reference toFIG. 1 but the invention is not restricted to this embodiment. FIG. 1 isa cross-sectional schematic view showing one embodiment of a dicingtape-integrated film for semiconductor back surface according to theinvention, which employs the film for flip chip type semiconductor backsurface according to the invention. In FIG. 1, 1 is a dicingtape-integrated film for semiconductor back surface (hereinaftersometimes also referred to as “dicing tape-integrated semiconductor backsurface protective film”, “film for semiconductor back surface withdicing tape”, or “semiconductor back surface protective film with dicingtape”), 2 is a film for flip chip type semiconductor back surface(hereinafter sometimes also referred to as “film for semiconductor backsurface” or “semiconductor back surface protective film”), 21 is a lasermarking layer, 22 is a wafer adhesion layer, 3 is a dicing tape, 31 is abase material, and 32 is a pressure-sensitive adhesive layer.

Incidentally, in the figures in the present specification, parts thatare unnecessary for the description are not given, and there are partsshown by magnifying, minifying, etc. in order to make the descriptioneasy.

As shown in FIG. 1, the dicing tape-integrated film 1 for semiconductorback surface has a constitution that the film 2 for semiconductor backsurface having a multilayered structure including the laser markinglayer 21 and the wafer adhesion layer 22 is formed, on thepressure-sensitive adhesive layer 32 of the dicing tape 3 having thebase material 31 and the pressure-sensitive adhesive layer 32 formed onthe base material 31, in a form that the pressure-sensitive adhesivelayer 32 comes into contact with the laser marking layer 21. The lasermarking layer 21 has a property that the elastic modulus (at 50° C.) is100 MPa or more. Moreover, the wafer adhesion layer 22 has a propertythat the elastic modulus (at 50° C.) is 10 MPa or less. Incidentally,the front surface of the film 2 for semiconductor back surface (thesurface to be attached onto the back surface of the wafer; i.e., thesurface of the wafer adhesion layer 22) may be protected with aseparator or the like during the period until it is attached to the backsurface of a wafer.

Incidentally, the dicing tape-integrated film for semiconductor backsurface may have a constitution that the film for semiconductor backsurface is formed on the pressure-sensitive adhesive layer of the dicingtape over the whole surface or may have a constitution that the film forsemiconductor back surface is partially formed. For example, as shown inFIG. 1, the dicing tape-integrated film for semiconductor back surfacemay have a constitution that the film for semiconductor back surface isformed, on the pressure-sensitive adhesive layer of the dicing tape,only on the part to which the semiconductor wafer is to be attached.

(Film for Flip Chip Type Semiconductor Back Surface)

The film for semiconductor back surface has a film shape. Since the filmfor semiconductor back surface has a multilayered structure containingthe wafer adhesion layer having an elastic modulus at 50° C. of 10 MPaor less and the laser marking layer having an elastic modulus at 50° C.of 100 MPa or more as mentioned above, in the cut-processing step(dicing step) of cutting a workpiece (semiconductor wafer) attached onthe film for semiconductor back surface (i.e., on the wafer adhesionlayer) into a chip shape, the film for semiconductor back surface has afunction of supporting the workpiece with close adhesion thereto andthus can exhibit close adhesiveness such that cut pieces are notscattered. Also, in the picking-up step after the dicing step, thechip-shaped workpiece individualized by dicing can be easily peeled fromthe dicing tape together with the film for semiconductor back surface.Moreover, after the picking-up step (after the chip-shaped workpieceindividualized by dicing is peeled from the dicing tape together withthe film for semiconductor back surface), even when the chip-shapedworkpiece (semiconductor chip) whose back surface is protected with thefilm for semiconductor back surface is placed (stored) on a support(e.g., a carrier tape), on that occasion (e.g., at the transportation orthe like in a state that the film is placed on the support), thechip-shaped workpiece is never or hardly attached to the support (e.g.,a top tape, a bottom tape, or the like of the carrier tape) through thefilm for semiconductor back surface and, at the utilization of thechip-shaped workpiece, it can be easily taken out from the support.Furthermore, after the picking-up step, the film for semiconductor backsurface can have a function of protecting the back surface of thechip-shaped workpiece. In addition, since the laser marking layerbecomes the outermost layer at the back surface side of the chip-shapedworkpiece, the film for semiconductor back surface has a function ofexhibiting an excellent laser marking property. Moreover, since thewafer adhesion layer has been attached to the back surface of thechip-shaped workpiece with an excellent close adhesiveness, lifting orthe like owing to insufficient adhesion is not observed, so that thechip-shaped workpiece can exhibit an excellent appearance property.Thus, since the film for semiconductor back surface has an excellentlaser marking property, laser marking can be performed to impart variouskinds of information such as literal information and graphicalinformation to the face on the non-circuit side of the chip-shapedworkpiece or a semiconductor device using the chip-shaped workpiece byutilizing a laser marking method through the film for semiconductor backsurface (i.e., the laser marking layer of the film for semiconductorback surface).

Incidentally, in the invention, the laser marking layer is preferablycolored in the film for semiconductor back surface, and furthermore,both layers of the wafer adhesion layer and the laser marking layer aresuitably both colored. Thus, when the laser marking layer (preferably,the wafer adhesion layer and the laser marking layer) is colored in thefilm for semiconductor back surface, a more excellent laser markingproperty can be exhibited. By controlling the color of coloring, itbecomes possible to observe the information (such as literal informationand graphical information) imparted by the marking with an excellentvisibility.

In particular, since the film for semiconductor back surface hasexcellent close adhesiveness to the semiconductor wafer or thesemiconductor chip, lifting or the like is not observed. Also, since thefilm for semiconductor back surface can exhibit an excellent appearanceproperty, a semiconductor device having an excellent value-addedappearance property can be obtained. For example, as a semiconductordevice, it is possible to classify products thereof by using differentcolors.

Moreover, by coloring the wafer adhesion layer and the laser markinglayer, the dicing tape and the film for semiconductor back surface canbe easily distinguished from each other, so that workability and thelike can be enhanced.

As above, the film for semiconductor back surface is used not fordie-bonding a semiconductor chip to an adherend such as a substrate butfor protecting the back surface (non-circuit face) of a semiconductorchip to be flip chip mounted (or having been flip chip mounted) and hasmost suitable function and constitution therefor. In this regard, adie-bonding film to be used in the use application of strongly adheringthe semiconductor chip to the adherend such as the substrate is anadhesive layer and is encapsulated with an encapsulating material, sothat the film does not have a laser marking layer and also does not havea laser marking property. Therefore, the film for semiconductor backsurface in the invention has a function or constitution different fromthat of a die-bonding film and thus it is not suitable to use the filmas a die-bonding film.

(Wafer Adhesion Layer)

The wafer adhesion layer is a layer exhibiting an excellent closeadhesiveness to a wafer (semiconductor wafer) and a layer coming intocontact with a back surface of the wafer. As a close adhesive force (anadhesive force) of the wafer adhesion layer to the wafer, it ispreferable that the adhesive force (peeling angle: 180°, tensile rate:300 mm/min) of the wafer adhesion layer to the wafer at 23° C. whenallowed to stand under an atmosphere of 23° C. for 20 minutes after thefilm for semiconductor back surface is attached to a semiconductor waferhaving a thickness of 0.6 mm at 50° C. by utilizing a thermal laminatingmethod in a form that the wafer adhesion layer comes into contact withthe wafer surface is 1 N/10 mm-width or more (for example, from 1 N/10mm-width to 10 N/10 mm-width), more preferably 2 N/10 mm-width or more(for example, from 2 N/10 mm-width to 10 N/10 mm-width) and still morepreferably 4 N/10 mm-width or more (for example, from 4 N/10 mm-width to10 N/10 mm-width). When the adhesive force (peeling angle: 180°, tensilerate: 300 min/min) of the wafer adhesion layer to the wafer is 1 N/10mm-width or more, an excellent adhesiveness as a wafer adhesion layer isexhibited.

In this regard, the adhesive force of the wafer adhesion layer to awafer is measured in the following manner. Specifically, apressure-sensitive adhesive tape (a trade name “BT315”, manufactured byNitto Denko Corporation) is attached to the face on the laser markinglayer side of the film for semiconductor back surface that contains thewafer adhesion layer and the laser marking layer, thereby reinforcingthe back surface. Then, a wafer (semiconductor wafer) having a thicknessof 0.6 mm is attached onto the front surface of the backsurface-reinforced film for semiconductor back surface having a lengthof 150 mm and a width of 10 mm by reciprocating a roller of 2 kg at 50°C. once. Thereafter, the laminate is allowed to stand on a hot plate(50° C.) for 2 minutes and then allowed to stand at ordinary temperature(about 23° C.) for 20 minutes. After standing, the backsurface-reinforced film for semiconductor back surface is peeled at atemperature of 23° C. under conditions of a peel angle of 180° and atensile rate of 300 mm/min by using a peel tester (a trade name“AUTOGRAPH AGS-J”, manufactured by Shimadzu Corporation). At this time,the peel force (N/10 mm-width) is measured by peeling at an interfacebetween the wafer adhesion layer and the wafer. The adhesive force inthe invention includes a pressure-sensitive adhesive force and a peelforce.

The adhesive force of the wafer adhesion layer to the wafer can becontrolled by the kind and content of the constituting resin component,the kind and content of the crosslinking agent, the kind and content ofthe filler, and the like.

Moreover, the wafer adhesion layer has a property that the elasticmodulus at 50° C. is 10 MPa or less. Thus, since the wafer adhesionlayer has a property that the elastic modulus at 50° C. is 10 MPa orless, the wafer adhesion layer exhibits a good close adhesiveness to awafer and can effectively exhibit a holding force of the wafer in thedicing step.

In the invention, the elastic modulus (at 50° C.) of the wafer adhesionlayer is not particularly restricted so long as the elastic modulus is10 MPa or less but is preferably 8 MPa or less (more preferably 6 MPa orless) and further preferably 5 MPa or less (particularly 3 MPa or less).A lower limit of the elastic modulus (at 50° C.) of the wafer adhesionlayer is not particularly restricted but is preferably 1 MPa or more andmore preferably 1.2 MPa or more (further preferably 1.5 MPa or more).Therefor; the elastic modulus (at 50° C.) of the wafer adhesion layercan be, for example, selected from the range of 1 to 10 MPa.

Incidentally, in the case that the wafer adhesion layer is formed of aresin composition containing a thermosetting resin as mentioned below,the thermosetting resin is usually in a uncured or partially curedstate, so that the elastic modulus of the film for semiconductor backsurface at 50° C. is usually an elastic modulus at 50° C. in a statethat the thermosetting resin is uncured or partially cured.

The elastic modulus (tensile storage elastic modulus E′) of the waferadhesion layer at 50° C. is determined by preparing a wafer adhesionlayer without lamination onto the dicing tape or the laser marking layerand measuring an elastic modulus in a tensile mode under conditions of asample width of 10 mm, a sample length of 22.5 mm, a sample thickness of0.2 mm, a frequency of 1 Hz, and a temperature elevating rate of 10°C./minute under a nitrogen atmosphere at a prescribed temperature (50°C.) using a dynamic viscoelasticity measuring apparatus “Solid AnalyzerRS A2” manufactured by Rheometrics Co. Ltd. and the measured elasticmodulus is regarded as a value of tensile storage elastic modulus E′obtained.

The elastic modulus of the wafer adhesion layer can be controlled by thekind and content of the resin components (the thermoplastic resin, thethermosetting resin), the kind and content of a filler such as silicafiller, and the like.

The wafer adhesion layer is usually protected with a separator but, whenthe separator is peeled, the layer becomes the outermost layer on oneface of the dicing tape-integrated film for semiconductor back surfaceand is used at the attachment of the dicing tape-integrated film forsemiconductor back surface to a wafer.

The wafer adhesion layer can be formed of a resin composition. As theresin composition for forming the wafer adhesion layer (sometimesreferred to as a “resin composition for the wafer adhesion layer”), aresin composition containing a thermoplastic resin component and athermosetting resin component can be suitably used. In the resincomposition for the wafer adhesion layer, as the thermoplastic resincomponent, the thermoplastic resins described (or exemplified) in thesection of the following (Thermoplastic resin component) and the likecan be used. On the other hand, as the thermosetting resin component,the thermosetting resins described (or exemplified) in the section ofthe following (Thermosetting resin component) and the like can be used.

Incidentally, in the invention, as shown below, an acrylic resin issuitable as the thermoplastic resin component in the resin compositionfor the wafer adhesion layer. On the other hand, as the thermosettingresin component in the resin composition for the wafer adhesion layer,an epoxy resin and a phenol resin are suitable. Therefore, as the resincomposition for the wafer adhesion layer, a resin composition containingan epoxy resin, a phenol resin and an acrylic resin is suitable. Sincethese resin components contain only a small amount of ionic impuritiesand have a high heat resistance, reliability of a semiconductor elementcan be secured.

In the resin composition for the wafer adhesion layer, from theviewpoint of the close adhesiveness to a semiconductor wafer, the ratioof the thermoplastic resin component is preferably less than 30% byweight (for example, 0% by weight or more and less than 30% by weight)and more preferably 28% by weight or less (further preferably 25% byweight or less) to the total amount of the resin components. In thisregard, in the resin composition for the wafer adhesion layer, when theratio of the thermoplastic resin component is too small, a film-formingproperty decreases. A lower limit of the ratio of the thermoplasticresin component of the resin composition for the wafer adhesion layer tothe total amount of the resin components is preferably 5% by weight ormore and more preferably 10% by weight or more (further preferably, 15%by weight or more) from the viewpoint of the film-forming property.Therefore, the ratio of the thermoplastic resin component in the resincomposition for the wafer adhesion layer can be selected, for example,from the range of 5% by weight and less than 30% by weight (preferably10% by weight and less than 30% by weight, more preferably 15% by weightand less than 30% by weight).

Of course, the ratio of the thermosetting resin component in the resincomposition for the wafer adhesion layer is a residual part obtained bysubtracting the ratio of the thermoplastic resin component from 100% byweight that is a ratio of the total amount of the resin components. Inthe case that the ratio of the thermoplastic resin component is 0% byweight to the total amount of the resin components, the resincomposition for the wafer adhesion layer becomes a resin composition(thermosetting resin composition) which contains only a thermosettingresin component as the resin component (contains no thermoplastic resincomponent).

The resin composition for the wafer adhesion layer may contain, inaddition to a crosslinking agent and a coloring agent, additives such asa filler, a flame retardant, a silane-coupling agent, an ion-trappingagent, an extender, an antiaging agent, an antioxidant, and a surfactantother than the resin components. As the crosslinking agent, for example,crosslinking agents described (or exemplified) in the section of thefollowing (Crosslinking agent) and the like can be used. As the coloringagent, for example, coloring agents described (or exemplified) in thesection of the following (Coloring agent) and the like can be used.

In this regard, by using the crosslinking agent, the close adhesivenessunder a high temperature can be enhanced and the heat resistance can beimproved. In the invention, in order to crosslink the resin componentsusing the crosslinking agent, it is preferable that a functional groupcapable of reacting with the crosslinking agent has been introduced intoa polymer of the resin components at its molecular chain end or thelike.

The wafer adhesion layer can be, for example, formed by utilizing acommonly used method including mixing a thermosetting resin componentsuch as an epoxy resin and/or a thermoplastic resin component such as anacrylic resin and optional solvent and other additives to prepare aresin composition and forming it into a film-shaped layer. Specifically,the wafer adhesion layer as a film-shaped layer can be formed, forexample, by a method including applying the resin composition on thelaser marking layer formed on the pressure-sensitive adhesive layer ofthe dicing tape; a method including applying the resin composition ontoan appropriate separator (such as release paper) to form a resin layerand then transferring (transcribing) it onto the laser marking layer; orthe like.

The thickness of the wafer adhesion layer is not particularly restrictedbut is, for example, preferably from 1 to 100 μm, more preferably from 2to 80 μm, further preferably 3 to 50 μm, and even more preferably 5 to40 μm. When the thickness of the wafer adhesion layer is too small,there is a possibility that a surface of the semiconductor wafer isexposed at the laser marking. On the other hand, when the thickness istoo large, there is a possibility that the semiconductor wafer is warpedafter thermal curing. In this regard, the wafer adhesion layer may haveany form of a single layer form and a laminated layer form.

(Laser Marking Layer)

The laser marking layer is a layer exhibiting an excellent laser markingproperty and a layer to be utilized at the laser marking on the backsurface of a semiconductor chip. Namely, the laser marking layer is alayer having a good laser processability. With regard to the laserprocessability of the laser marking layer, it is important thatprocessed depth (depth) at irradiation of the laser marking layer with alaser [wavelength: 532 nm, a laser generation apparatus (a trade name“MD-S9900” manufactured by Keyence Corporation)] under a condition of anintensity of 1.0 W is 2 μm or more. An upper limit thereof is notparticularly restricted and may be the same value as the thickness ofthe laser marking layer. Specifically, the laser processed depth of thelaser marking layer can be, for example, selected from the range of 2 to25 μm and is preferably 3 μm or more (from 3 to 20 μm) and morepreferably 5 μm or more (from 5 to 15 μm). When the processed depth[wavelength: 532 nm, a laser generation apparatus (a trade name“MD-S9900” manufactured by Keyence Corporation)] that is a measure ofthe laser processability of the laser marking layer is 2 μm or moreunder a condition of an intensity of 1.0 W, an excellent laser markingproperty is exhibited. In this regard, when the laser processed depth ofthe laser marking layer is the same value as the thickness of the lasermarking layer, the laser also reaches the wafer adhesion layer laminatedto the laser marking layer by the irradiation with the laser and thusthe wafer adhesion layer is also processed in some cases. Moreover, thelaser marking layer is processed by the irradiation with the laser, andexamples of the processing include a processing in which organiccomponents and the like are burnt to change the composition.

Incidentally, the processed depth that is a measure of the laserprocessability of the laser marking layer is a value determined byirradiating the laser marking layer (which may be a laminate with thewafer adhesion layer) with a laser [wavelength: 532 nm, a lasergeneration apparatus (a trade name “MD-S9900” manufactured by KeyenceCorporation)] under a condition of an intensity of 1.0 W and measuringthe processed depth obtained by the irradiation with the laser.

The laser processability of the laser marking layer can be controlled bythe kind and content of the resin components, the kind and content ofthe crosslinking agent, the kind and content of the filler, and thelike.

Moreover, the laser marking layer has a property that the elasticmodulus at 50° C. is 100 MPa or more. Thus, since the laser markinglayer has a property that the elastic modulus at 50° C. is 100 MPa ormore, after the chip-shaped workpiece is peeled from thepressure-sensitive adhesive layer of the dicing tape together with thefilm for semiconductor back surface (film for semiconductor back surfacehaving the wafer adhesion layer and the laser marking layer), at thetime when the chip-shaped workpiece whose back surface is protected withthe film for semiconductor back surface is placed on a support (e.g., acarrier tape) to perform transportation or the like, the attachment ofthe laser marking layer, which becomes the outermost layer of thechip-shaped workpiece protected with the film for semiconductor backsurface, to a support (e.g., a top tape, a bottom tape, or the like ofthe carrier tape) can be effectively suppressed or prevented.

In the invention, the elastic modulus (at 50° C.) of the laser markinglayer is not particularly restricted so long as the elastic modulus is100 MPa or more but is preferably 500 MPa or more (more preferably 1 GPaor more) and further preferably 2 GPa or more (further preferably 3 GPaor more). An upper limit of the elastic modulus (at 50° C.) of the lasermarking layer is not particularly restricted but is preferably 50 GPa orless (more preferably 30 GPa or less) and further preferably 20 GPa orless (further preferably 10 GPa or less). Therefore, the elastic modulus(at 50° C.) of the laser marking layer can be, for example, selectedfrom the range of 100 MPa to 50 GPa.

Incidentally, in the case that the laser marking layer is formed of aresin composition containing a thermosetting resin as mentioned below,the thermosetting resin is usually in a uncured or partially curedstate, so that the elastic modulus of the laser marking layer at 50° C.is usually an elastic modulus at 50° C. in a state that thethermosetting resin is uncured or partially cured.

The elastic modulus (tensile storage elastic modulus E′) of the lasermarking layer at 50° C. is determined by preparing a laser marking layerwithout lamination onto the wafer adhesion layer and measuring anelastic modulus in a tensile mode under conditions of a sample width of10 mm, a sample length of 22.5 mm, a sample thickness of 0.2 mm, afrequency of 1 Hz, and a temperature elevating rate of 10° C./minuteunder a nitrogen atmosphere at a prescribed temperature (50° C.) using adynamic viscoelasticity measuring apparatus “Solid Analyzer RS A2”manufactured by Rheometrics Co. Ltd. and the measured elastic modulus isregarded as a value of tensile storage elastic modulus E′ obtained.

The elastic modulus of the laser marking layer can be controlled by thekind and content of the resin components (the thermoplastic resin, thethermosetting resin), the kind and content of a filler such as silicafiller, and the like.

Incidentally, the laser marking layer is attached to thepressure-sensitive adhesive layer of the dicing tape in the dicingtape-integrated film for semiconductor back surface but, in thesemiconductor chip picked up after the dicing step, it becomes theoutermost layer at the back surface side of the semiconductor chip.

The laser marking layer can be formed of a resin composition. As theresin composition for forming the laser marking layer (sometimesreferred to as a “resin composition for the laser marking layer”), aresin composition containing a thermoplastic resin component and athermosetting resin component can be suitably used. In the resincomposition for the laser marking layer, as the thermoplastic resincomponent, the thermoplastic resins described (or exemplified) in thesection of the following (Thermoplastic resin component) and the likecan be used. On the other hand, as the thermosetting resin component,the thermosetting resins described (or exemplified) in the section ofthe following (Thermosetting resin component) and the like can be used.

Incidentally, in the invention, as shown below, an acrylic resin issuitable as the thermoplastic resin component in the resin compositionfor the laser marking layer. On the other hand, as the thermosettingresin component in the resin composition for the laser marking layer, anepoxy resin and a phenol resin axe suitable. Therefore, as the resincomposition for the laser marking layer, a resin composition containingan epoxy resin, a phenol resin and an acrylic resin is suitable. Sincethese resin components contains only a small amount of ionic impuritiesand have a high heat resistance, reliability of a semiconductor elementcan be secured.

In the resin composition for the laser marking layer, the ratio of thethermoplastic resin component is preferably 30% by weight or more (forexample, 30% by weight or more and 100% by weight or less) to the totalamount of the resin components from the viewpoint of the laser markingproperty. In the resin composition for the laser marking layer, when theratio of the thermoplastic resin component is too large, heat-resistantperformance decreases. Therefore, an upper limit of the ratio of thethermoplastic resin component in the resin composition for the lasermarking layer to the total amount of the resin components is preferably90% by weight or less, more preferably 80% by weight or less, andfurther preferably 60% by weight or less (even more preferably 50% byweight or less) from the viewpoint of the heat resistance. Accordingly,the ratio of the thermoplastic resin component in the resin compositionfor the laser marking layer can be, for example, selected from the rangeof 30% by weight or more and 90% by weight or less (preferably 30% byweight or more and 80% by weight or less, more preferably 30% by weightor more and 60% by weight or less, and further preferably 30% by weightor more and 50% by weight or less).

Of course, the ratio of the thermosetting resin component in the resincomposition for the laser marking layer is a residual part obtained bysubtracting the ratio of the thermoplastic resin component from 100% byweight that is a ratio of total amount of the resin components. In thecase that the ratio of the thermoplastic resin component is 100% byweight to the total amount of the resin components, the resincomposition for the laser marking layer becomes a resin composition(thermoplastic resin composition) which contains only a thermoplasticresin component as the resin component (contains no thermosetting resincomponent).

The resin composition for the laser marking layer may contain, inaddition to a crosslinking agent and a coloring agent, additives such asa filler, a flame retardant, a silane-coupling agent, an ion-trappingagent, an extender, an antiaging agent, an antioxidant, and a surfactantas components other than the resin components. As the crosslinkingagent, for example, crosslinking agents described (or exemplified) inthe section of the following (Crosslinking agent) and the like can beused. As the coloring agent, for example, coloring agents described (orexemplified) in the section of the following (Coloring agent) and thelike can be used.

In this regard, by using the crosslinking agent, the close adhesivenessunder a high temperature can be enhanced and the heat resistance can beimproved. In the invention, in order to crosslink the resin componentswith the crosslinking agent, it is important that a functional groupcapable of reacting with the crosslinking agent has been introduced intoa polymer of the resin components at its molecular chain end or thelike.

The laser marking layer can be, for example, formed by utilizing acommonly used method including mixing a thermosetting resin componentsuch as an epoxy resin and/or a thermoplastic resin component such as anacrylic resin and optional solvent and other additives to prepare aresin composition and forming it to a film-shaped layer. Specifically,the laser marking layer as a film-shaped layer can be formed, forexample, by a method including applying the resin composition on thepressure-sensitive adhesive layer of the dicing tape; a method includingapplying the resin composition on an appropriate separator (such asrelease paper) to form a resin layer and then transferring(transcribing) it onto the pressure-sensitive adhesive layer of thedicing tape or onto the wafer adhesion layer; or the like.

The thickness of the laser marking layer is not particularly restrictedbut is, for example, preferably from 1 to 100 μm, more preferably from 2to 80 μm, further preferably 3 to 50 μm, and even more preferably 5 to40 μm. When the thickness of the laser marking layer is too small, thereis a possibility that the semiconductor wafer surface is exposed at thelaser marking. On the other hand, when the thickness is too large, thereis a possibility that the semiconductor wafer is warped after thermalcuring. In this regard, the laser marking layer may have any form of asingle layer form and a laminated layer form.

(Thermoplastic Resin Component)

In the resin composition for the wafer adhesion layer and the resincomposition for the laser marking layer, examples of the thermoplasticresin component include natural rubber, butyl rubber, isoprene rubber,chloroprene rubber, ethylene-vinyl acetate copolymers, ethylene-acrylicacid copolymers, ethylene-acrylic acid ester copolymers, polybutadieneresins, polycarbonate resins, thermoplastic polyimide resins, polyamideresins such 6-Nylon and 6,6-Nylon, phenoxy resins, acrylic resins,saturated polyester resins such as PET (polyethylene terephthalate) andPBT (polybutylene terephthalate), polyamideimide resins, or fluorocarbonresins. The thermoplastic resin component may be employed singly or in acombination of two or more kinds. Among these thermoplastic resincomponents, acrylic resins containing only a small amount of ionicimpurities, having a high heat resistance, and capable of securingreliability of a semiconductor element are preferable.

The acrylic resins are not particularly restricted, and examples thereofinclude polymers containing, as component(s), one kind or two or morekinds of esters of acrylic acid or methacrylic acid having a straightchain or branched alkyl group having 30 or less carbon atoms, preferably4 to 18 carbon atoms. Namely, in the invention, the acrylic resin has abroad meaning also including a methacrylic resin. Examples of the alkylgroup include a methyl group, an ethyl group, a propyl group, anisopropyl group, an n-butyl group, a t-butyl group, an isobutyl group, apentyl group, an isopentyl group, a hexyl group, a heptyl group, a2-ethylhexyl group, an octyl group, an isooctyl group, a nonyl group, anisononyl group, a decyl group, an isodecyl group, an undecyl group, adodecyl group (lauryl group), a tridecyl group, a tetradecyl group, asteparyl group, and an octadecyl group.

Moreover, other monomers for forming the acrylic resins (monomers otherthan the alkyl esters of acrylic acid or methacrylic acid having thealkyl group having 30 or less carbon atoms) are not particularlyrestricted, and examples thereof include carboxyl group-containingmonomers such as acrylic acid, methacrylic acid, carboxylethyl acrylate,carboxylpentyl acrylate, itaconic acid, maleic acid, fumaric acid, andcrotonic acid; acid anhydride monomers such as maleic anhydride anditaconic anhydride; hydroxyl group-containing monomers such as2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate,4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate,8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate,12-hydroxylauryl (meth)acrylate, and(4-hydroxymethylcyclohexyl)-methylacrylate; sulfonic acid-containingmonomers such as styrenesulfonic acid, allylsulfonic acid,2-(meth)acrylamido-2-methylpropanesulfonic acid,(meth)acrylamidopropanesulfonic acid, sulfopropyl (meth)acrylate, and(meth)acryloyloxynaphthalenesulfonic acid; and phosphoric acidgroup-containing monomers such as 2-hydroxyethylacryloyl phosphate.

Such resins may be synthesized according to known methods orcommercially available products may be used.

(Thermosetting Resin Component)

In the resin composition for the wafer adhesion layer and the resincomposition for the laser marking layer, examples of the thermosettingresin component include epoxy resins and phenol resins as well as aminoresins, unsaturated polyester resins, polyurethane resins, siliconeresins, and thermosetting polyimide resins. The thermosetting resincomponent may be employed singly or in a combination of two or morekinds. As the thermosetting resin component, epoxy resins containingonly a small amount of ionic impurities which corrode a semiconductorelement are suitable. Further, a phenol resin is preferably used as acuring agent of the epoxy resins.

The epoxy resin is not particularly restricted and, for example, adifunctional epoxy resin or a polyfunctional epoxy resin such as abisphenol A type epoxy resin, a bisphenol F type epoxy resin, abisphenol S type epoxy resin, a brominated bisphenol A type epoxy resin,a hydrogenated bisphenol A type epoxy resin, a bisphenol AF type epoxyresin, a biphenyl type epoxy resin, a naphthalene type epoxy resin, afluorene type epoxy resin, a phenol novolak type epoxy resin, ano-cresol novolak type epoxy resin, a trishydroxyphenylmethane type epoxyresin or a tetraphenylolethane type epoxy resin, or an epoxy resin suchas a hydantoin type epoxy resin, a trisglycidylisocyanurate type epoxyresin or a glycidylamine type epoxy resin may be used.

As the epoxy resin, among those exemplified above, a novolak type epoxyresin, a biphenyl type epoxy resin, a trishydroxyphenylmethane typeepoxy resin, and a tetraphenylolethane type epoxy resin are preferable.This is because these epoxy resins are rich in reactivity with a phenolresin as a curing agent and are superior in heat resistance and thelike.

The epoxy resins may be synthesized according to known methods, orcommercially available products may be used.

Furthermore, the phenol resin acts as a curing agent of the epoxy resin,and examples thereof include novolak type phenol resins such as phenolnovolak resins, phenol aralkyl resins, cresol novolak resins,tert-butylphenol novolak resins, and nonylphenol novolak resins; resoltype phenol resins; and polyoxystyrenes such as poly-p-oxystyrene. Thephenol resin may be employed singly or in a combination of two or morekinds. Among these phenol resins, phenol novolak resins and phenolaralkyl resins are preferable. This is because connection reliability ofthe semiconductor device can be enhanced.

The phenol resin may be synthesized according to known methods orcommercially available products may be used.

The mixing ratio of the epoxy resin to the phenol resin is preferablymade, for example, such that the hydroxyl group in the phenol resinbecomes 0.5 to 2.0 equivalents per equivalent of the epoxy group in theepoxy resin component. It is more preferably 0.8 to 1.2 equivalents.That is, when the mixing ratio becomes outside the range, a curingreaction does not proceed sufficiently, and the characteristics of theepoxy resin cured product tends to deteriorate.

A thermal curing-accelerating catalyst for the epoxy resins and thephenol resins is not particularly restricted and can be suitablyselected from known thermal curing-accelerating catalysts and used. Thethermal curing-accelerating catalyst may be employed singly or in acombination of two or more kinds. As the thermal curing-acceleratingcatalyst, for example, an amine-based curing-accelerating catalyst, aphosphorus-based curing-accelerating catalyst, an imidazole-basedcuring-accelerating catalyst, a boron-based curing-acceleratingcatalyst, or a phosphorus-boron-based curing-accelerating catalyst canbe used.

(Crosslinking Agent)

The crosslinking agent to be used in the resin composition for the waferadhesion layer and the resin composition for the laser marking layer isnot particularly restricted and can be appropriately selected from knowncrosslinking agents. Specifically, examples of the crosslinking agentsinclude not only isocyanate-based crosslinking agents, epoxy-basedcrosslinking agents, melamine-based crosslinking agents, andperoxide-based crosslinking agents but also urea-based crosslinkingagents, metal alkoxide-based crosslinking agents, metal chelate-basedcrosslinking agents, metal salt-based crosslinking agents,carbodiimide-based crosslinking agents, oxazoline-based crosslinkingagents, aziridine-based crosslinking agents, and amine-basedcrosslinking agents. As the crosslinking agent, an isocyanate-basedcrosslinking agent or an epoxy-based crosslinking agent is suitable. Thecrosslinking agent may be employed singly or in a combination of two ormore kinds.

Examples of the isocyanate-based crosslinking agents include loweraliphatic polyisocyanates such as 1,2-ethylene diisocyanate,1,4-butylene diisocyanate, and 1,6-hexamethylene diisocyanate; alicyclicpolyisocyanates such as cyclopentylene diisocyanate, cyclohexylenediisocyanate, isophorone diisocyanate, hydrogenated tolylenediisocyanate, and hydrogenated xylylene diisocyanate; and aromaticpolyisocyanates such as 2,4-tolylene diisocyanate, 2,6-tolylenediisocyanate, 4,4′-diphenylmethane diisocyanate, and xylylenediisocyanate. In addition, a trimethylolpropane/tolylene diisocyanatetrimer adduct [a trade name “COLONATE L” manufactured by NipponPolyurethane Industry Co., Ltd.], a trimethylolpropane/hexamethylenediisocyanate trimer adduct [a trade name “COLONATE HL” manufactured byNippon Polyurethane Industry Co., Ltd.], and the like are also used.Moreover, examples of the epoxy-based crosslinking agents includeN,N,N′,N′-tetraglycidyl-m-xylenediamine, diglycidylaniline,1,3-bis(N,N-glycidylaminomethyl)cyclohexane, 1,6-hexanediol diglycidylether, neopentyl glycol diglycidyl ether, ethylene glycol diglycidylether, propylene glycol diglycidyl ether, polyethylene glycol diglycidylether, polypropylene glycol diglycidyl ether, sorbitol polyglycidylether, glycerol polyglycidyl ether, pentaerythritol polyglycidyl ether,polyglycerol polyglycidyl ether, sorbitan polyglycidyl ether,trimethylolpropnane polyglycidyl ether, adipic acid diglycidyl ester,o-phthalic acid diglycidyl ester, triglycidyl-tris(2-hydroxyethyl)isocyanurate, resorcin diglycidyl ether, and bisphenol-S-diglycidylether, as well as epoxy-based resins having two or more epoxy groups inthe molecule.

The amount of the crosslinking agent to be used is not particularlyrestricted and can be appropriately selected depending on the degree ofthe crosslinking. Specifically, it is preferable that the amount of thecrosslinking agent to be used is, for example, from 0.05 to 7 parts byweight based on 100 parts by weight of the resin component (polymercomponent) (particularly, a polymer having a functional group at themolecular chain end). When the amount of the crosslinking agent is from0.05 to 7 parts by weight based on 100 parts by weight of the polymercomponent, close adhesiveness and a cohesion property can be exhibitedat a high level.

In the invention, instead of the use of the crosslinking agent ortogether with the use of the crosslinking agent, it is also possible toperform a crosslinking treatment by irradiation with an electron beam,ultraviolet light, or the like.

(Coloring Agent)

In the invention, the film for semiconductor back surface is preferablycolored. Specifically, at least one of the wafer adhesion layer and thelaser marking layer is preferably colored. Particularly, it is morepreferable that at least the laser marking layer is colored, and it isfurthermore preferable that both layers of the wafer adhesion layer andthe laser marking layer are both colored.

In the invention, in the case where both layers of the wafer adhesionlayer and the laser marking layer are both colored, the wafer adhesionlayer and the laser marking layer may be colored with the same color ormay be colored with different colors.

As above, in the case where the film for semiconductor back surface iscolored (the case where the film is neither colorless nor transparent),the color shown by coloring is not particularly limited but, forexample, is preferably dark color such as black, blue or red color, andblack color is more preferable.

In the invention, dark color basically means a dark color having L*,defined in L*a*b* color space, of 60 or smaller (from 0 to 60),preferably 50 or smaller (from 0 to 50), and more preferably 40 orsmaller (from 0 to 40).

Moreover, black color basically means a black-based color having L*,defined in L*a*b* color space, of 35 or smaller (from 0 to 35),preferably 30 or smaller (from 0 to 30), and more preferably 25 orsmaller (from 0 to 25). In this regard, in the black color, each of a*and b*, defined in the L*a*b* color space, can be suitably selectedaccording to the value of L*. For example, both of a* and b* are withinthe range of preferably from −10 to 10, more preferably from −5 to 5,and further preferably −3 to 3 (particularly 0 or about 0).

In the invention, L*, a*, and b* defined in the L*a*b* color space canbe determined by a measurement with a color difference meter (a tradename “CR-200” manufactured by Minolta Ltd; color difference meter). TheL*a*b* color space is a color space recommended by the CommissionInternationale de l'Eclairage (CIE) in 1976, and means a color spacecalled CIE1976(L*a*b*) color space. Also, the L*a*b* color space isdefined in Japanese Industrial Standards in JIS 28729.

At coloring of the wafer adhesion layer or the laser marking layer,according to an objective color, a colorant (coloring agent) can beused. As such a colorant, various dark-colored colorants such asblack-colored colorants, blue-colored colorants, and red-coloredcolorants can be suitably used and black-colored colorants are moresuitable. The colorant may be any of pigments and dyes. The colorant maybe employed singly or in combination of two or more kinds. In thisregard, as the dyes, it is possible to use any forms of dyes such asacid dyes, reactive dyes, direct dyes, disperse dyes, and cationic dyes.Moreover, also with regard to the pigments, the form thereof is notparticularly limited and can be suitably selected and used among knownpigments.

In particular, when a dye is used as a colorant, the dye becomes in astate that it is homogeneously or almost homogeneously dispersed bydissolution in the film for semiconductor back surface, so that the filmfor semiconductor back surface (as a result, the dicing tape-integratedfilm for semiconductor back surface) having a homogeneous or almosthomogeneous color density can be easily produced. Accordingly, when adye is used as a colorant, the film for semiconductor back surface inthe dicing tape-integrated film for semiconductor back surface can havea homogeneous or almost homogeneous color density and can enhance amarking property and an appearance property.

The black-colored colorant is not particularly restricted and can be,for example, suitably selected from inorganic black-colored pigments andblack-colored dyes. Moreover, the black-colored colorant may be acolorant mixture in which a cyan-colored colorant (blue-green colorant),a magenta-colored colorant (red-purple colorant), and a yellow-coloredcolorant (yellow colorant) are mixed. The black-colored colorant may beemployed singly or in a combination of two or more kinds. Of course, theblack-colored colorant may be used in combination with a colorant of acolor other than black.

Specific examples of the black-colored colorant include carbon black(such as furnace black, channel black, acetylene black, thermal black,or lamp black), graphite (black lead), copper oxide, manganese dioxide,azo-type pigments (such as azomethine azo black), aniline black,perylene black, titanium black, cyanine black, active charcoal, ferrite(such as non-magnetic ferrite or magnetic ferrite), magnetite, chromiumoxide, iron oxide, molybdenum disulfide, a chromium complex, a compositeoxide type black pigment, and an anthraquinone type organic blackpigment.

As the black-colored colorant, black-colored dyes such as C.I. SolventBlack 3, 7, 22, 27, 29, 34, 43, 70, C.I. Direct Black 17, 19, 22, 32,38, 51, 71, C.I. Acid Black 1, 2, 24, 26, 31, 48, 52, 107, 109, 110,119, 154, and C.I. Disperse Black 1, 3, 10, 24; black-colored pigmentssuch as C.I. Pigment Black 1, 7; and the like can be utilized.

As such black-colored colorants, for example, a trade name “Oil BlackBY”, a trade name “Oil Black BS”, a trade name “Oil Black HBB”, a tradename “Oil Black 803”, a trade name “Oil Black 860”, a trade name “OilBlack 5970”, a trade name “Oil Black 5906”, a trade name “Oil Black5905” (manufactured by Orient Chemical Industries Co., Ltd.), and thelike are commercially available.

Examples of colorants other than the black-colored colorant includecyan-colored colorants, magenta-colored colorants, and yellow-coloredcolorants.

Examples of the cyan-colored colorants include cyan-colored dyes such asC.I. Solvent Blue 25, 36, 60, 70, 93, 95; C.I. Acid Blue 6 and 45;cyan-colored pigments such as C.I. Pigment Blue 1, 2, 3, 15, 15:1, 15:2,15:3, 15:4, 15:5, 15:6, 16, 17, 17:1, 18, 22, 25, 56, 60, 63, 65, 66;C.I. Vat Blue 4, 60; and C.I. Pigment Green 7.

Moreover, among the magenta colorants, examples of magenta-colored dyeinclude C.I, Solvent Red 1, 3, 8, 23, 24, 25, 27, 30, 49, 52, 58, 63,81, 82, 83, 84, 100, 109, 111, 121, 122; C.I. Disperse Red 9; C.I.Solvent Violet 8, 13, 14, 21, 27; C.I. Disperse Violet 1; C.I. Basic Red1, 2, 9, 12, 13, 14, 15, 17, 18, 22, 23, 24, 27, 29, 32, 34, 35, 36, 37,38, 39, 40; C.I. Basic Violet 1, 3, 7, 10, 14, 15, 21, 25, 26, 27 and28.

Among the magenta-colored colorants, examples of magenta-colored pigmentinclude C.I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 39, 40, 41, 42,48:1, 48:2, 48:3, 48:4, 49, 49:1, 50, 51, 52, 52:2, 53:1, 54, 55, 56,57:1, 58, 60, 60:1, 63, 63:1, 63:2, 64, 64:1, 67, 68, 81, 83, 87, 88,89, 90, 92, 101, 104, 105, 106, 108, 112, 114, 122, 123, 139, 144, 146,147, 149, 150, 151, 163, 166, 168, 170, 171, 172, 175, 176, 177, 178,179, 184, 185, 187, 190, 193, 202, 206, 207, 209, 219, 222, 224, 238,245; C.I. Pigment Violet 3, 9, 19, 23, 31, 32, 33, 36, 38, 43, 50; C.I.Vat Red 1, 2, 10, 13, 15, 23, 29 and 35.

Moreover, examples of the yellow-colored colorants includeyellow-colored dyes such as C.I. Solvent Yellow 19, 44, 77, 79, 81, 82,93, 98, 103, 104, 112, and 162; yellow-colored pigments such as C.I.Pigment Orange 31, 43; C.I. Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11,12, 13, 14, 15, 16, 17, 23, 24, 34, 35, 37, 42, 53, 55, 65, 73, 74, 75,81, 83, 93, 94, 95, 97, 98, 100, 101, 104, 108, 109, 110, 113, 114, 116,117, 120, 128, 129, 133, 138, 139, 147, 150, 151, 153, 154, 155, 156,167, 172, 173, 180, 185, 195; C.I. Vat Yellow 1, 3, and 20.

Various colorants such as cyan-colored colorants, magenta-coloredcolorants, and yellow-colorant colorants may be employed singly or in acombination of two or more kinds, respectively. In this regard, in thecase that two or more kinds of various colorants such as cyan-coloredcolorants, magenta-colored colorants, and yellow-colorant colorants areused, the mixing ratio (or blending ratio) of these colorants is notparticularly restricted and can be suitably selected according to thekind of each colorant, an objective color, and the like.

Incidentally, in the case of using a colorant mixture formed by mixing acyan-colored colorant, a magenta-colored colorant and a yellow-coloredcolorant as the black-colored colorant, these colorants may be usedsingly or in a combination of two or more kinds. The mixing ratio (orblending ratio) of the cyan-colored colorant, the magenta-coloredcolorant and the yellow-colored colorant in the mixed ink composition isnot particularly restricted as long as a black-based color (e.g., ablack-based color having L*, a*, and b*, defined in L*a*b* color space,within the above ranges) can be exhibited, and may be suitably selectedaccording to the type of each colorant and the like. The contents of thecyan-colored colorant, the magenta-colored colorant and theyellow-colored colorant in the mixed ink composition can be suitablyselected, for example, within a range, with respect to the total amountof the colorants, of cyan-colored colorant/magenta-coloredcolorant/yellow-colored colorant=10% by weight to 50% by weight/10% byweight to 50% by weight/10% by weight to 50% by weight (preferably 20%by weight to 40% by weight/20% by weight to 40% by weight/20% by weightto 40% by weight).

The content of the colorant can be suitably selected from a range of 0.1to 10% by weight in the resin composition which forms the wafer adhesionlayer or the laser marking layer (excluding solvent(s)) and ispreferably from 0.5 to 8% by weight and more preferably from 1 to 5% byweight.

(Other Additives)

In the invention, as mentioned above, in the resin composition for thewafer adhesion layer and the resin composition for the laser markinglayer, other additives can be appropriately blended according to thenecessity. As the other additives, in addition to a filler, a flameretardant, a silane-coupling agent, and an ion-trapping agent, additivessuch as an extender, an antiaging agent, an antioxidant, and asurfactant may be used.

The filler may be any of an inorganic filler and an organic filler butan inorganic filler is suitable. By blending a filler such as aninorganic filler, imparting of electric conductivity to the film forsemiconductor back surface, improvement of the thermal conductivity ofthe film for semiconductor back surface, control of elastic modulus ofthe film for semiconductor back surface, and the like can be achieved.In this regard, the film for semiconductor back surface may beelectrically conductive or non-conductive. Examples of the inorganicfiller include various inorganic powders composed of silica, clay,gypsum, calcium carbonate, barium sulfate, alumina oxide, berylliumoxide, ceramics such as silicone carbide and silicone nitride, metals oralloys such as aluminum, copper, silver, gold, nickel, chromium, lead,tin, zinc, palladium, and solder, carbon, and the like. The filler maybe employed singly or in a combination of two or more kinds.Particularly, the filler is suitably silica and more suitably fusedsilica. The average particle diameter of the inorganic filler ispreferably within the range of 0.1 to 80 μm. The average particlediameter of the inorganic filler can be measured by a laserdiffraction-type particle size distribution measurement apparatus.

The blending amount of the filler (e.g., inorganic filler) is preferably80 parts by weight or less (0 to 80 parts by weight) and more preferably0 to 70 parts by weight based on 100 parts by weight of the total amountof the organic resin components.

Examples of the flame retardant include antimony trioxide, antimonypentoxide, and brominated epoxy resins. The flame retardant may beemployed singly or in a combination of two or more kinds. Examples ofthe silane coupling agent includeβ-(3,4-epoxycyclohexyl)ethyltrimethoxysilane,γ-glycidoxypropyltrimethoxysilane, andγ-glycidoxypropylmethyldiethoxysilane. The silane coupling agent may beemployed singly or in a combination of two or more kinds. Examples ofthe ion-trapping agent include hydrotalcites and bismuth hydroxide. Theion-trapping agent may be employed singly or in a combination of two ormore kinds.

The thickness of the film for semiconductor back surface (the thicknessof the whole film including the wafer adhesion layer and the lasermarking layer) is not particularly restricted but can be, for example,appropriately selected from the range of about 2 to 200 μm. In theinvention, the thickness of the film for semiconductor back surface ispreferably about 4 to 160 μm, more preferably about 6 to 100 μm, andfurther preferably 10 to 80 μm. Incidentally, the film for semiconductorback surface may have other layer(s) as layer(s) between the waferadhesion layer and the laser marking layer.

In this regard, in the film for semiconductor back surface, in the casethat the wafer adhesion layer and/or the laser marking layer are formedof a resin composition containing a thermosetting resin such as an epoxyresin, the film for semiconductor back surface is in a state where thethermosetting resin is uncured or partially cured at a stage before thefilm is applied to a semiconductor wafer. In this case, after it isapplied to the semiconductor wafer (specifically, usually, at the timewhen an encapsulating material is cured in the flip chip bonding step),the thermosetting resin in the wafer adhesion layer and/or the lasermarking layer in the film for semiconductor back surface is completelyor almost completely cured.

As above, since the wafer adhesion layer and/or the laser marking layerin the film for semiconductor back surface are in a state where athermosetting resin is uncured or partially cured even when the layerscontain the thermosetting resin, the gel fraction of the wafer adhesionlayer and/or that of the laser marking layer in the film forsemiconductor back surface is not particularly restricted but can be,for example, suitably selected from the range of 50% by weight or less(from 0 to 50% by weight) and is preferably 30% by weight or less (from0 to 30% by weight) and more preferably 10% by weight or less (from 0 to10% by weight). The gel fraction of the wafer adhesion layer and that ofthe laser marking layer in the film for semiconductor back surface canbe measured by the following measuring method.

<Gel Fraction Measuring Method>

About 0.1 g of a sample is sampled from the wafer adhesion layer or thelaser marking layer in the film for semiconductor back surface andprecisely weighed (Weight of Sample) and, after the sample is wrapped ina mesh-type sheet, it is immersed in about 50 mL of toluene at roomtemperature for 1 week. Thereafter, a solvent-insoluble matter (contentin the mesh-type sheet) is taken out of the toluene and dried at 130° C.for about 2 hours, the solvent-insoluble matter after drying is weighed(Weight after Immersion and Drying), and then the gel fraction (% byweight) is calculated according to the following equation (a).

Gel Fraction (% by weight)=[(Weight after Immersion and Drying)/(Weightof Sample)]×100  (a)

Incidentally, the gel fraction of the wafer adhesion layer or that ofthe laser marking layer in the film for semiconductor back surface canbe controlled by the kind and content of the resin components, the kindand content of the crosslinking agent, heating temperature and heatingtime, and the like.

As the film for semiconductor back surface (film for semiconductor backsurface having the wafer adhesion layer and the laser marking layer,particularly the laser marking layer) according to the invention, theelastic modulus (tensile storage elastic modulus E′) at 23° C. ispreferably 1 GPa or more, more preferably 2 GPa or more, and furtherpreferably 3 GPa or more. When the elastic modulus of the film forsemiconductor back surface (particularly elastic modulus of the lasermarking layer) is 1 GPa or more, at the time when a chip-shapedworkpiece is peeled from the pressure-sensitive adhesive layer of thedicing tape together with the film for semiconductor back surface andthen the film for semiconductor back surface is placed on a support(e.g., a carrier tape) to perform transportation or the like, theattachment of the film for semiconductor back surface to the support(e.g., a top tape or a bottom tape in the carrier tape) can besuppressed or prevented. In this regard, in the case that the waferadhesion layer and/or the laser marking layer in the film forsemiconductor back surface are formed of a resin composition containinga thermosetting resin, as mentioned above, the thermosetting resin isusually in a uncured or partially cured state, so that the elasticmodulus of the film for semiconductor back surface (elastic modulus ofthe film for semiconductor back surface having the wafer adhesion layerand the laser marking layer, particularly elastic modulus of the lasermarking layer) at 23° C. is an elastic modulus at 23° C. in a state thatthe thermosetting resin is uncured or partially cured.

The elastic modulus (tensile storage elastic modulus E′) of the film forsemiconductor back surface at 23° C. is determined by preparing a filmfor semiconductor back surface formed of a wafer adhesion layer and alaser marking layer without lamination onto the dicing tape andmeasuring elastic modulus in a tensile mode under conditions of a samplewidth of 10 mm, a sample length of 22.5 mm, a sample thickness of 0.2mm, a frequency of 1 Hz, and a temperature elevating rate of 10°C./minute under a nitrogen atmosphere at a prescribed temperature (23°C.) using a dynamic viscoelasticity measuring apparatus “Solid AnalyzerRS A2” manufactured by Rheometrics Co. Ltd. and the measured elasticmodulus is regarded as a value of tensile storage elastic modulus E′obtained.

The elastic modulus of the film for semiconductor back surface can becontrolled by the kind and content of the resin components of the waferadhesion layer and those of the laser marking layer (thermoplastic resinand/or thermosetting resin), the kind and content of the filler such assilica filler, and the like.

A light transmittance (visible light transmittance) of the film forsemiconductor back surface in a visible light region (wavelength: from400 nm to 800 nm) is not particularly restricted but is, for example,preferably in the range of not more than 20% (from 0% to 20%), morepreferably in the range of not more than 10% (from 0% to 10%), andespecially preferably in the range of not more than 5% (from 0% to 5%).When the light transmittance of the film for semiconductor back surfacein a visible light region is not more than 20%, the visible lighttransmits through the film for semiconductor back surface and reaches asemiconductor chip, whereby adverse influences against the semiconductorchip can be diminished.

The visible light transmittance (%) of the film for semiconductor backsurface can be controlled by the kind and content of the resincomponents constituting the film for semiconductor back surface, thekind and content of a coloring agent (for example, a pigment and a dye),the kind and content of a filler and the like.

The visible light transmittance (%) can be, for example, calculated inthe following manner. That is, the film for semiconductor back surfacehaving a thickness (average thickness) of 20 μm is prepared withoutbeing laminated on the dicing tape. Next, the film for semiconductorback surface is irradiated with visible light using “ABSORPTION SPECTROPHOTOMETER” (a trade name of Shimadzu Corporation). The visible lighthas a wavelength of from 400 nm to 800 nm. The light intensity of thevisible light which has transmitted through the film for semiconductorback surface by this irradiation can be calculated according to thefollowing expression.

Visible light transmittance (%)=[(Light intensity of visible light aftertransmitting through the film for semiconductor back surface)/(Initiallight intensity of visible light)]×100

The foregoing calculation method of the light transmittance (%) can alsobe applied to the calculation of a light transmittance (%) of a film forsemiconductor back surface whose thickness is not 20 μm. Specifically,in accordance with the Lambert-Beer law, an absorbance A₂₀ in the caseof the thickness of 20 μm can be calculated as follows.

A ₂₀ =α×L ₂₀ ×C  (1)

(In the formula, L₂₀ is a length of light path, α is an absorbanceindex, C is a concentration of sample.)

In addition, an absorbance A_(X) in the case of the thickness of X (μm)can be calculated as follows.

A _(X) =α×L _(X) ×C  (2)

Moreover, absorbance A₂₀ in the case of the thickness of 20 μm can becalculated as follows.

A₂₀=−log₁₀T₂₀  (3)

(In the formula, T₂₀ is a light transmittance in the case of thethickness of 20 μm.)

From the formulae (1) to (3) above, absorbance A_(X) can be representedby the following formula.

A _(X) =A ₂₀×(L _(X) /L ₂₀)=−[log₁₀(T ₂₀)]×(L _(X) /L ₂₀)

Therefore, a light transmittance T_(X) (%) in the case of the thicknessof X μm can be calculated as follows:

T_(X)=10^(−Ax)

wherein A _(X)=−[log₁₀(T ₂₀)]×(L _(X) /L ₂₀).

Also, the fact that the thickness of the film for semiconductor backsurface in the foregoing calculation method of a light transmittance (%)is regulated to 20 μm does not particularly restrict the thickness ofthe film for semiconductor back surface of the invention. The value of“20 μm” is a thickness employed for the sake of convenience at themeasurement.

In the invention, the film for semiconductor back surface preferably hasa low moisture absorbance. Specifically, as the film for semiconductorback surface, the moisture absorbance when the film is allowed to standunder an atmosphere of temperature of 85° C. and humidity of 85% RH for168 hours is preferably 1% by weight or less and more preferably 0.8% byweight or less. By regulating the moisture absorbance of the film forsemiconductor back surface (after standing under an atmosphere oftemperature of 85° C. and humidity of 85% RH for 168 hours) to 1% byweight or less, the laser marking property can be enhanced. Moreover,for example, the generation of voids can be suppressed or prevented inthe reflow step. The moisture absorbance of the film for semiconductorback surface can be regulated, for example, by changing the amount ofthe inorganic filler to be added. The moisture absorbance (% by weight)of the film for semiconductor back surface is a value calculated from aweight change when the film is allowed to stand under an atmosphere oftemperature of 85° C. and humidity of 85% RH for 168 hours (see thefollowing expression). In the case that the wafer adhesion layer and/orthe laser marking layer in the film for semiconductor back surfaceis/are formed of a resin composition containing a thermosetting resin,the moisture absorbance of the film for semiconductor back surface is avalue calculated from a weight change when the film is allowed to standunder an atmosphere of a temperature of 85° C. and a humidity of 85% RHfor 168 hours after thermal curing.

Moisture absorbance (% by weight)=[{(Weight after allowing the coloredfilm for semiconductor back surface to stand)−(Weight before allowingthe colored film for semiconductor back surface to stand)}/(Weightbefore allowing the colored film for semiconductor back surface tostand)]×100

Moreover, in the invention, the film for semiconductor back surfacepreferably has a small ratio of volatile matter. Specifically, as thefilm for semiconductor back surface, the ratio of weight decrease(weight decrease ratio) after heating at a temperature of 250° C. for 1hour is preferably 2% by weight or less, more preferably 1% by weight orless and still more preferably 0.8% by weight or less. By regulating theweight decrease ratio of the film for semiconductor back surface (afterheating at a temperature of 250° C. for 1 hour) to 2% by weight or less,the laser marking property can be enhanced. Moreover, for example, thegeneration of cracks in a package can be suppressed or prevented in thereflow step. The weight decrease ratio of the film for semiconductorback surface can be regulated, for example, by adding an inorganicsubstance capable of reducing the crack generation at lead-free solderreflow, e.g., an inorganic filler such as silica or alumina. The weightdecrease ratio (% by weight) of the film for semiconductor back surfaceis a value calculated from a weight change when the film is heated at250° C. for 1 hour (see the following expression). In the case that thewafer adhesion layer and/or the laser marking layer in the film forsemiconductor back surface is/are formed of a resin compositioncontaining a thermosetting resin, the weight decrease ratio of the filmfor semiconductor back surface is a value calculated from a weightchange when the film is heated at a temperature of 250° C. for 1 hourafter thermal curing.

Weight decrease ratio (% by weight)=[{(Weight before allowing the filmfor semiconductor back surface to stand)−(Weight after allowing the filmfor semiconductor back surface to stand)}/(Weight before allowing thefilm for semiconductor back surface to stand)]×100

The film for semiconductor back surface (preferably the wafer adhesionlayer) is preferably protected by a separator (release liner, not shownin figures). The separator has a function as a protective material forprotecting the film for semiconductor back surface (preferably the waferadhesion layer) until it is practically used. Moreover, the separatorcan be further used as a supporting base material at the time when thefilm for semiconductor back surface is transferred to thepressure-sensitive adhesive layer on the base material of the dicingtape. The separator is peeled when attaching a workpiece onto the filmfor semiconductor back surface of the dicing tape-integrated film forsemiconductor back surface. As the separator, a film of polyethylene orpolypropylene, as well as a plastic film (such as polyethyleneterephthalate), a paper, or the like whose surface is coated with areleasing agent such as a fluorine-based releasing agent or a long-chainalkyl acrylate-based releasing agent can also be used. The separator canbe formed by a conventionally known method. Moreover, the thickness orthe like of the separator is not particularly restricted.

Moreover, the film for semiconductor back surface according to theinvention has a multilayered structure including the wafer adhesionlayer and the laser marking layer but may contain other layers (e.g., anintermediate layer, a light-shielding layer, a reinforcing layer, acolored layer, a base material layer, an electromagnetic wave-shieldinglayer, a heat conductive layer, a pressure-sensitive adhesive layer,etc.) between the wafer adhesion layer and the laser marking layer aslong as the wafer adhesion layer comes into contact with the backsurface of a wafer and the laser marking layer is attached to thepressure-sensitive adhesive layer of the dicing tape in the dicingtape-integrated film for semiconductor back surface and also becomes theoutermost layer at the back surface side of a semiconductor chip in thesemiconductor chip picked up after the dicing step.

Dicing Tape

The dicing tape includes a base material and a pressure-sensitiveadhesive layer formed on the base material. Thus, the dicing tapesufficiently has a constitution that the base material and thepressure-sensitive adhesive layer are laminated. The base material(supporting base material) can be used as a supporting material for thepressure-sensitive adhesive layer and the like. As the base material,for example, suitable thin materials, e.g., paper-based base materialssuch as paper; fiber-based base materials such as fabrics, non-wovenfabrics, felts, and nets; metal-based base materials such as metal foilsand metal plates; plastic base materials such as plastic films andsheets; rubber-based base materials such as rubber sheets; foamed bodiessuch as foamed sheets; and laminates thereof [laminates of plastic basedmaterials with other base materials, laminates of plastic films (orsheets) each other, etc.] can be used. In the invention, as the basematerial, plastic base materials such as plastic films and sheets can besuitably employed. Examples of raw materials for such plastic materialsinclude olefinic resins such as polyethylene (PE), polypropylene (PP),and ethylene-propylene copolymers; copolymers using ethylene as amonomer component, such as ethylene-vinyl acetate copolymers (EVA),ionomer resins, ethylene-(meth)acrylic acid copolymers, andethylene-(meth)acrylic acid ester (random, alternating) copolymers;polyesters such as polyethylene terephthalate (PET), polyethylenenaphthalate (PEN), and polybutylene terephthalate (PBT); acrylic resins;polyvinyl chloride (PVC); polyurethanes; polycarbonates; polyphenylenesulfide (PPS); amide-based resins such as polyamides (Nylon) and wholearomatic polyamides (aramide); polyether ether ketones (PEEK);polyimides; polyetherimides; polyvinylidene chloride; ABS(acrylonitrile-butadiene-styrene copolymers); cellulose-based resins;silicone resins; and fluorinated resins. Moreover, as the material ofthe base material, a polymer such as a cross-linked body of each of theabove resins can also be used. These raw materials may be employedsingly or in a combination of two or more kinds.

In the case that a plastic base material is used as the base material,deformation properties such as an elongation degree may be controlled bya stretching treatment or the like.

The thickness of the base material is not particularly restricted andcan be appropriately selected depending on strength, flexibility,intended purpose of use, and the like. For example, the thickness isgenerally 1000 μm or less (e.g., 1 to 1000 μm), preferably 10 to 500 μm,further preferably 20 to 300 μm, and further preferably about 30 to 200μm but is not limited thereto. In this regard, the base material mayhave any form of a single layer form and a laminated layer form.

A commonly used surface treatment, e.g., an oxidation treatment by achemical or physical treatment such as a chromate treatment, ozoneexposure, flame exposure, exposure to high-voltage electric shock, or anionized radiation treatment, or a coating treatment with an undercoatingagent may be applied onto the surface of the base material, in order toenhance close adhesiveness with the adjacent layer, holding properties,etc.

Incidentally, the base material may contain various additives (acoloring agent, a filler, a plasticizer, an antiaging agent, anantioxidant, a surfactant, a flame retardant, etc.) within the rangewhere the advantages and the like of the invention are not impaired.

The pressure-sensitive adhesive layer is formed of a pressure-sensitiveadhesive and has pressure-sensitive adhesiveness. Such apressure-sensitive adhesive is not particularly restricted and can besuitably selected among known pressure-sensitive adhesives.Specifically, as the pressure-sensitive adhesive, a pressure-sensitiveadhesive having the above-mentioned characteristics can be suitablyselected and used among known pressure-sensitive adhesives such asacrylic pressure-sensitive adhesives, rubber-based pressure-sensitiveadhesives, vinyl alkyl ether-based pressure-sensitive adhesives,silicone-based pressure-sensitive adhesives, polyester-basedpressure-sensitive adhesives, polyamide-based pressure-sensitiveadhesives, urethane-based pressure-sensitive adhesives, fluorine-basedpressure-sensitive adhesives, styrene-diene block copolymer-basedpressure-sensitive adhesives, and creep characteristic-improvingpressure-sensitive adhesives in which a heat-meltable resin having amelting point of about 200° C. or lower is mixed into thesepressure-sensitive adhesives (see, e.g., JP-A-56-61468, JP-A-61-174857,JP-A-63-17981, JP-A-56-13040, etc., each of which herein incorporated byreference). Moreover, as the pressure-sensitive adhesives,radiation-curable pressure-sensitive adhesives (or energy ray-curablepressure-sensitive adhesives) or heat-expandable pressure-sensitiveadhesives can be also used. The pressure-sensitive adhesive may beemployed singly or in a combination of two or more kinds.

In the invention, as the pressure-sensitive adhesive, acrylicpressure-sensitive adhesives and rubber-based pressure-sensitiveadhesives can be suitably used and particularly, acrylicpressure-sensitive adhesives are suitable. As the acrylicpressure-sensitive adhesives, there may be mentioned acrylicpressure-sensitive adhesives in which an acrylic polymer (homopolymer orcopolymer) using one or two or more kinds of alkyl (meth)acrylates asmonomer components is used as the base polymer.

Examples of the alkyl (meth)acrylates in the acrylic pressure-sensitiveadhesives include alkyl (meth)acrylates such as methyl (meth)acrylate,ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate,butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate,t-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate,heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl(meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl(meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl(meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate,tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl(meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate,nonadecyl (meth)acrylate, and eicosyl (meth)acrylate. As the alkyl(meth)acrylates, alkyl (meth)acrylates having an alkyl group having 4 to18 carbon atoms are suitable. Incidentally, the alkyl group of the alkyl(meth)acrylate may be linear or branched.

The above-mentioned acrylic polymer may contain units corresponding toother monomer components (copolymerizable monomer components)polymerizable with the alkyl (meth)acrylates for the purpose ofmodifying cohesive force, heat resistance, crosslinking ability, and thelike. Examples of such copolymerizable monomer components includecarboxyl group-containing monomers such as (meth)acrylic acid (acrylicacid or methacrylic acid), carboxyethyl acrylate, carboxypentylacrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid;acid anhydride group-containing monomers such as maleic anhydride anditaconic anhydride; hydroxyl group-containing monomers such ashydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl(meth)acrylate, hydroxyhexyl (meth)acrylate, hydroxyoctyl(meth)acrylate, hydroxydecyl (meth)acrylate, hydroxylauryl(meth)acrylate, and (4-hydroxymethylcyclohexyl)methyl methacrylate;sulfonic acid group-containing monomers such as styrenesulfonic acid,allylsulfonic acid, 2-(meth)acrylamide-2-methylpropanesulfonic acid,(meth)acrylamidepropanesulfonic acid, sulfopropyl (meth)acrylate, and(meth)acryloyloxynaphthalenesulfonic acid; phosphoric acidgroup-containing monomers such as 2-hydroxyethylacryloyl phosphate;(N-substituted)amide-based monomers such as (meth)acrylamide,N,N-dimethyl(meth)acrylamide, N-butyl(meth)acrylamide,N-methylol(meth)acrylamide, and N-methylolpropane(meth)acrylamide;aminoalkyl (meth)acrylate-based monomers such as aminoethyl(meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, andt-butylaminoethyl (meth)acrylate; alkoxyalkyl (meth)acrylate-basedmonomers such as methoxyethyl (meth)acrylate and ethoxyethyl(meth)acrylate; cyanoacrylate monomers such as acrylonitrile andmethacrylonitrile; epoxy group-containing acrylic monomers such asglycidyl (meth)acrylate; styrene-based monomers such as styrene andα-methylstyrene; vinyl ester-based monomers such as vinyl acetate andvinyl propionate; olefin-based monomers such as isoprene, butadiene, andisobutylene; vinyl ether-based monomers such as vinyl ether;nitrogen-containing monomers such as N-vinylpyrrolidone,methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine,vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole,vinyloxazole, vinylmorpholine, N-vinylcarboxylic acid amides, andN-vinylcaprolactam; maleimide-based monomers such asN-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, andN-phenylmaleimide; itaconimide-based monomers such asN-methylitaconimide, N-ethylitaconirnide, N-butylitaconimide,N-octylitaconimide, N-2-ethylhexylitaconimide, N-cyclohexylitaconimide,and N-laurylitaconimide; succinimide-based monomers such asN-(meth)acryloyloxymethylenesuccinimide,N-(meth)acryloyl-6-oxyhexamethylenesuccinimide, andN-(meth)acryloyl-8-oxyoctamethylenesuccinimide; glycol-based acrylicester monomers such as polyethylene glycol (meth)acrylate, polypropyleneglycol (meth)acrylate, methoxyethylene glycol (meth)acrylate, andmethoxypolypropylene glycol (meth)acrylate; acrylic acid ester-basedmonomers having a heterocycle, a halogen atom, a silicon atom, or thelike, such as tetrahydrofurfuryl (meth)acrylate, fluorine(meth)acrylate, and silicone (meth)acrylate; polyfunctional monomerssuch as hexanediol di(meth)acrylate, (poly)ethylene glycoldi(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentylglycol di(meth)acrylate, pentaerythritol di(meth)acrylate,trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate,dipentaerythritol hexa(meth)acrylate, epoxy acrylate, polyesteracrylate, urethane acrylate, divinylbenzene, butyl di(meth)acrylate, andhexyl di(meth)acrylate; and the like. These copolymerizable monomercomponents may be employed singly or in a combination of two or morekinds.

In the case that a radiation-curable pressure-sensitive adhesive (or anenergy ray-curable pressure-sensitive adhesive) is used as apressure-sensitive adhesive, examples of the radiation-curablepressure-sensitive adhesive (composition) include internal typeradiation-curable pressure-sensitive adhesives in which a polymer havinga radically reactive carbon-carbon double bond in the polymer side chainor main chain is used as the base polymer, radiation-curablepressure-sensitive adhesives in which a UV curable monomer component oroligomer component is blended into the pressure-sensitive adhesive, andthe like. Moreover, in the case that the heat-expandablepressure-sensitive adhesive is used as the pressure-sensitive adhesive,there may be mentioned heat-expandable pressure-sensitive adhesivescontaining a pressure-sensitive adhesive and a foaming agent(particularly, heat-expandable microsphere); and the like as theheat-expandable pressure-sensitive adhesive.

In the invention, the pressure-sensitive adhesive layer may containvarious additives (e.g., a tackifying resin, a coloring agent, athickener, an extender, a filler, a plasticizer, an antiaging agent, anantioxidant, a surfactant, a crosslinking agent, etc.) within the rangewhere the advantages of the invention are not impaired.

The crosslinking agent is not particularly restricted and knowncrosslinking agents can be used. Specifically, as the crosslinkingagent, not only isocyanate-based crosslinking agents, epoxy-basedcrosslinking agents, melamine-based crosslinking agents, andperoxide-based crosslinking agents but also urea-based crosslinkingagents, metal alkoxide-based crosslinking agents, metal chelate-basedcrosslinking agents, metal salt-based crosslinking agents,carbodiimide-based crosslinking agents, oxazoline-based crosslinkingagents, aziridine-based crosslinking agents, amine-based crosslinkingagents, and the like may be mentioned, and isocyanate-based crosslinkingagents and epoxy-based crosslinking agents are suitable. Specificexamples of the isocyanate-based crosslinking agents and the epoxy-basedcrosslinking agents include compounds (specific examples) specificallyexemplified in the paragraphs concerning the film for semiconductor backsurface. The crosslinking agent may be employed singly or in acombination of two or more kinds. Incidentally, the amount of thecrosslinking agent is not particularly restricted.

In the invention, instead of the use of the crosslinking agent ortogether with the use of the crosslinking agent, it is also possible toperform the crosslinking treatment by irradiation with an electron beamor ultraviolet light.

The pressure-sensitive adhesive layer can be, for example, formed byutilizing a commonly used method including mixing a pressure-sensitiveadhesive and optional solvent and other additives and then shaping themixture into a sheet-like layer. Specifically, the pressure-sensitiveadhesive layer can be, for example, formed by a method includingapplying a mixture containing a pressure-sensitive adhesive and optionalsolvent and other additives on a base material; a method includingapplying the above-mentioned mixture on an appropriate separator (suchas a release paper) to form a pressure-sensitive adhesive layer and thentransferring (transcribing) it on a base material; or the like.

The thickness of the pressure-sensitive adhesive layer is notparticularly restricted and, for example, is preferably about 5 to 300μm, more preferably 5 to 200 μm, further preferably 5 to 100 μm, andeven more preferably 7 to 50 μm. When the thickness of thepressure-sensitive adhesive layer is within the above-mentioned range,an appropriate pressure-sensitive adhesive force can be exhibited. Thepressure-sensitive adhesive layer may be either a single layer or amulti layer.

Moreover, the thickness of the dicing tape (thickness of the whole tapeincluding the base material and the pressure-sensitive adhesive layer)can be, for example, selected from the range of 6 to 1300 μm, and ispreferably 15 to 700 μm, more preferably 25 to 400 μm, and furtherpreferably 37 to 250 μm.

Incidentally, in the invention, the dicing tape-integrated film forsemiconductor back surface can be made to have an antistatic function.Owing to this constitution, the circuit can be prevented from breakingdown owing to the generation of electrostatic energy at the time ofclose adhesion (at the time of adhesion) and at the time of peelingthereof or owing to charging of a workpiece (a semiconductor wafer,etc.) by the electrostatic energy. Imparting of the antistatic functioncan be performed by an appropriate manner such as a method of adding anantistatic agent or a conductive substance to the base material, thepressure-sensitive adhesive layer, and the film for semiconductor backsurface or a method of providing a conductive layer composed of acharge-transfer complex, a metal film, or the like onto the basematerial. As these methods, a method in which an impurity ion having afear of changing quality of the semiconductor wafer is difficult togenerate is preferable. Examples of the conductive substance (conductivefiller) to be blended for the purpose of imparting conductivity,improving thermal conductivity, and the like include a sphere-shaped, aneedle-shaped, or a flake-shaped metal powder of silver, aluminum, gold,copper, nickel, a conductive alloy, or the like; a metal oxide such asalumina; amorphous carbon black, and graphite. However, the film forsemiconductor back surface is preferably non-conductive from theviewpoint of having no electric leakage.

In the invention, the dicing tape may be prepared as mentioned above andused or a commercially available product may be used.

Moreover, the dicing tape-integrated film for semiconductor back surfacemay be formed in a form where it is wound as a roll or may be formed ina form where the sheet (film) is laminated. For example, in the casethat the film has the form where it is wound as a roll, the film forsemiconductor back surface may be wound as a roll in a state that thefilm is protected by a separator according to needs, whereby the filmcan be prepared as a dicing tape-integrated film for semiconductor backsurface in a state or form where it is wound as a roll. In this regard,the dicing tape-integrated film for semiconductor back surface in thestate or form where it is wound as a roll may be constituted by the basematerial, the pressure-sensitive adhesive layer formed on one surface ofthe base material, the film for semiconductor back surface formed on thepressure-sensitive adhesive layer, and a releasably treated layer (rearsurface treated layer) formed on the other surface of the base material.

Incidentally, the thickness of the dicing tape-integrated film forsemiconductor back surface (total thickness of the thickness of the filmfor semiconductor back surface including the wafer adhesion layer andthe laser marking layer and the thickness of the dicing tape includingthe base material and the pressure-sensitive adhesive layer) can be, forexample, selected from the range of 8 to 1500 μm, and it is preferablyfrom 20 to 850 μm, more preferably 31 to 500 μm, and further preferably47 μm to 330 μm.

In the dicing tape-integrated film for semiconductor back surface, aratio of the thickness of the film for semiconductor back surface to thethickness of the pressure-sensitive adhesive layer of the dicing tape isnot particularly restricted, but it can be, for example, suitablyselected from the range of 150/5 to 3/100 in terms of the ratio of(thickness of the film for semiconductor back surface)/(thickness of thepressure-sensitive adhesive layer of the dicing tape). The ratio ispreferably from 100/5 to 3/50 and more preferably 60/5 to 3/40. When theratio of the thickness of the film for semiconductor back surface to thethickness of the pressure-sensitive adhesive layer of the dicing tape iswithin the above-mentioned range, an appropriate pressure-sensitiveadhesive force can be exhibited, and excellent dicing property andpicking-up property can be exhibited.

Moreover, in the dicing tape-integrated film for semiconductor backsurface, the ratio of the thickness of the film for semiconductor backsurface to the thickness of the dicing tape (total thickness of the basematerial and the pressure-sensitive adhesive layer) is not particularlyrestricted but can be, for example, appropriately selected from therange of 150/50 to 3/500 in terms of (thickness of the film forsemiconductor back surface)/(thickness of the dicing tape), and ispreferably 100/50 to 3/300 and more preferably 60/50 to 3/150. When theratio of the thickness of the film for semiconductor back surface to thethickness of the dicing tape is within the range of 150/50 to 3/500, apicking-up property is good and generation of lateral residue at dicingcan be suppressed or prevented.

As above, by controlling the ratio of the thickness of the film forsemiconductor back surface to the thickness of the pressure-sensitiveadhesive layer of the dicing tape or the ratio of the thickness of thefilm for semiconductor back surface to the thickness of the dicing tape(total thickness of the base material and the pressure-sensitiveadhesive layer) in the dicing tape-integrated film for semiconductorback surface, a dicing property at the dicing step, a picking-upproperty at the picking-up step, and the like can be improved and thedicing tape-integrated film for semiconductor back surface can beeffectively utilized from the dicing step of the semiconductor wafer tothe flip chip bonding step of the semiconductor chip.

(Producing Method of Dicing Tape Integrated Film for Semiconductor BackSurface)

The producing method of the dicing tape-integrated film forsemiconductor back surface of the invention is described while using thedicing tape-integrated film 1 for semiconductor back surface as anexample. First, the base material 31 can be formed by a conventionallyknown film-forming method. Examples of the film-forming method include acalendar film-forming method, a casting method in an organic solvent, aninflation extrusion method in a closely sealed system, a T-die extrusionmethod, a co-extrusion method, and a dry laminating method.

Next, the pressure-sensitive adhesive layer 32 is formed by applying apressure-sensitive adhesive composition onto the base material 31,followed by drying (by crosslinking under heating according to needs).Examples of the application method include roll coating, screen coating,and gravure coating. In this regard, the pressure-sensitive adhesivecomposition may be directly applied onto the base material 31 to formthe pressure-sensitive adhesive layer 32 on the base material 31, or thepressure-sensitive adhesive composition may be applied onto a releasepaper or the like whose surface has been subjected to a releasabletreatment to form a pressure-sensitive adhesive layer, which is thentransferred onto the base material 31 to form the pressure-sensitiveadhesive layer 32 on the base material 31. Thus, a dicing tape 3 isprepared by forming the pressure-sensitive adhesive layer 32 on the basematerial 31.

On the other hand, the wafer adhesion layer 22 is formed by applying aresin composition that is a forming material for forming the waferadhesion layer 22 (resin composition for the wafer adhesion layer) ontoa release paper so as to have a prescribed thickness after drying andfurther drying under prescribed conditions (in the case that thermalcuring is necessary, performing a heating treatment and drying accordingto needs). Subsequently, the laser marking layer 21 is formed byapplying a resin composition that is a forming material for forming thelaser marking layer 21 (resin composition for the laser marking layer)onto the wafer adhesion layer 22 so as to have a prescribed thicknessafter drying and further drying under prescribed conditions (in the casethat thermal curing is necessary, performing a heating treatment anddrying according to needs), thereby manufacturing a film 2 forsemiconductor back surface having a laminate structure of the lasermarking layer 21 and the wafer adhesion layer 22. The film 2 forsemiconductor back surface is formed on the pressure-sensitive adhesivelayer 32 by transferring the film 2 for semiconductor back surface ontothe pressure-sensitive adhesive layer 32 in a form that the lasermarking layer 21 comes into contact with the pressure-sensitive adhesivelayer 32. In this regard, the film 2 for semiconductor back surface canbe also formed on the pressure-sensitive adhesive layer 32 by applyingthe resin composition for the laser marking layer onto thepressure-sensitive adhesive layer 32 to form the laser marking layer 21and further applying the resin composition for the wafer adhesion layeronto the laser marking layer 21 to form the wafer adhesion layer 22.Consequently, the dicing tape-integrated film 1 for semiconductor backsurface according to the invention can be obtained. Incidentally, in thecase that thermal curing is performed at the formation of the film 2 forsemiconductor back surface, it is important to perform the thermalcuring to such a degree that a partial curing is achieved butpreferably, the thermal curing is not performed.

The dicing tape-integrated film for semiconductor back surface of theinvention can be suitably used at the production of a semiconductordevice including the flip chip bonding step. Namely, the dicingtape-integrated film for semiconductor back surface of the invention isused at the production of a flip chip-mounted semiconductor device andthus the flip chip-mounted semiconductor device is produced in acondition or form where the film for semiconductor back surface of thedicing tape-integrated film for semiconductor back surface is attachedto the back surface of the semiconductor chip. Therefore, the dicingtape-integrated film for semiconductor back surface of the invention canbe used for a flip chip-mounted semiconductor device (a semiconductordevice in a state or form where the semiconductor chip is fixed to anadherend such as a substrate by a flip chip bonding method).

(Semiconductor Wafer)

The workpiece (semiconductor wafer) is not particularly restricted aslong as it is a known or commonly used semiconductor wafer and can beappropriately selected and used among semiconductor wafers made ofvarious materials. In the invention, as the semiconductor wafer, asilicon wafer can be suitable used.

(Production Process of Semiconductor Device)

The process for producing a semiconductor device according to theinvention is not particularly restricted as long as it is a process forproducing a semiconductor device using the above-mentioned dicingtape-integrated film for semiconductor back surface. For example, aproduction process including the following steps and the like processmay be mentioned:

a step of attaching a workpiece onto the film for semiconductor backsurface (i.e., onto the wafer adhesion layer of the film forsemiconductor back surface) of the dicing tape-integrated film forsemiconductor back surface (mounting step);

a step of dicing the workpiece to form a chip-shaped workpiece (dicingstep);

a step of peeling the chip-shaped workpiece from the pressure-sensitiveadhesive layer of the dicing tape together with the film forsemiconductor back surface (picking-up step); and

a step of fixing the chip-shaped workpiece to an adherend by flip chipbonding (flip chip bonding step).

More specifically, as the process for producing a semiconductor device,for example, a semiconductor device can be produced by using the dicingtape-integrated film for semiconductor back surface according to theinvention, after the separator optionally provided on the film forsemiconductor back surface is appropriately peeled off, as follows.Hereinafter, referring to FIGS. 2A to 2D, the process is described whileusing, as an example, the case that the dicing tape-integrated film 1for semiconductor back surface is employed.

FIGS. 2A to 2D are cross-sectional schematic views showing oneembodiment of the process for producing a semiconductor device using thedicing tape-integrated film for semiconductor back surface according tothe invention. In FIGS. 2A to 2D, 4 is a workpiece (semiconductorwafer), 5 is a chip-shaped workpiece (semiconductor chip), 51 is a bumpformed at the circuit face side of the semiconductor chip 5, 6 is anadherend, 61 is a conductive material for conjunction adhered to aconnecting pad of the adherend 6, and 1, 2, 21, 22, 3, 31, and 32 are adicing tape-integrated film for semiconductor back surface, a film forsemiconductor back surface, a laser marking layer, a wafer adhesionlayer, a dicing tape, a base material, and a pressure-sensitive adhesivelayer, respectively, as mentioned above.

(Mounting Step)

First, as shown in FIG. 2A, the semiconductor wafer (workpiece) 4 isattached (press-bonded) onto the wafer adhesion layer of the film 2 forsemiconductor back surface in the dicing tape-integrated film 1 forsemiconductor back surface to fix the semiconductor wafer by closeadhesion and holding (mounting step). The present step is usuallyperformed while pressing with a pressing means such as a pressing roll.

(Dicing Step)

Next, as shown in FIG. 2B, the semiconductor wafer 4 is diced.Consequently, the semiconductor wafer 4 is cut into a prescribed sizeand individualized (is formed into small pieces) to producesemiconductor chips (chip-shaped workpieces) 5. The dicing is performedaccording to a normal method from the circuit face side of thesemiconductor wafer 4, for example. Moreover, the present step canadopt, for example, a cutting method called full-cut that forms a slitreaching the dicing tape-integrated film 1 for semiconductor backsurface. In the invention, it is important that the workpiece is fullycut (completely cut) in the dicing step. On this occasion, it isimportant that the workpiece is diced together with the film forsemiconductor back surface while completely cutting the film forsemiconductor back surface. Namely, it is important that the presentstep is a step of forming a chip-shaped workpiece by dicing theworkpiece together with the film for semiconductor back surface. In thisregard, at the dicing of the workpiece together with the film forsemiconductor back surface, the dicing can be performed in a form wherea slit is not formed on the dicing tape or in a form where a slit isformed at least partially also on the dicing tape (preferably partiallyso that the dicing tape is not cut). The dicing apparatus used in thepresent step is not particularly restricted, and a conventionally knownapparatus can be used. Further, since the semiconductor wafer 4 isadhered and fixed by the dicing tape-integrated film 1 for semiconductorback surface, chip crack and chip fly can be suppressed, as well as thedamage on the semiconductor wafer 4 can also be suppressed. In thisregard, when the film 2 for semiconductor back surface (laser markinglayer and wafer adhesion layer) is formed of a resin compositioncontaining an epoxy resin, generation of adhesive extrusion from thefilm for semiconductor back surface can be suppressed or prevented atthe cut surface even when it is cut by dicing. As a result,re-attachment (blocking) of the cut surfaces themselves can besuppressed or prevented and thus the picking-up to be mentioned belowcan be further conveniently performed.

In the case that the dicing tape-integrated film for semiconductor backsurface is expanded, the expansion can be performed using aconventionally known expanding apparatus. The expanding apparatus has adoughnut-shaped outer ring capable of pushing the dicing tape-integratedfilm for semiconductor back surface downward through a dicing ring andan inner ring which has a diameter smaller than the outer ring andsupports the dicing tape-integrated film for semiconductor back surface.Thanks to the expanding step, it is possible to prevent the damage ofadjacent semiconductor chips through contact with each other in thepicking-up step to be mentioned below.

(Picking-Up Step)

In order to collect the semiconductor chip 5 that is adhered and fixedto the dicing tape-integrated film 1 for semiconductor back surface,picking-up of the semiconductor chip 5 is performed as shown in FIG. 2Cto peel the semiconductor chip 5 together with the film 2 forsemiconductor back surface from the dicing tape 3. The method ofpicking-up is not particularly restricted, and conventionally knownvarious methods can be adopted. For example, there may be mentioned amethod including pushing up each semiconductor chip 5 from the basematerial 31 side of the dicing tape-integrated film 1 for semiconductorback surface with a needle and picking-up the pushed semiconductor chip5 with a picking-up apparatus. In this regard, the picked-upsemiconductor chip 5 has been protected with the film 2 forsemiconductor back surface including the laser marking layer 21 and thewafer adhesion layer 22 at the back surface (also referred to as anon-circuit face, a non-electrode-formed face, etc.),

(Flip Chip Bonding Step)

As shown in FIG. 2D, the picked-up semiconductor chip 5 is fixed to anadherend such as a substrate by a flip chip bonding method (flip chipmounting method). Specifically, the semiconductor chip 5 is fixed to theadherend 6 according to a usual manner in a form where the circuit face(also referred to as a front face, circuit pattern-formed face,electrode-formed face, etc.) of the semiconductor chip 5 is opposed tothe adherend 6. For example, the bump 51 formed at the circuit face ofthe semiconductor chip 5 is brought into contact with a conductivematerial 61 (such as solder) for conjunction attached to a connectingpad of the adherend 6 and the conductive material is melted underpressing, whereby electric connection between the semiconductor chip 5and the adherend 6 can be secured and the semiconductor chip 5 can befixed to the adherend 6. In this regard, at the fixing of thesemiconductor chip 5 to the adherend 6, it is important that theopposing faces of the semiconductor chip 5 and the adherend 6 and thegap are washed in advance and an encapsulating material (such as anencapsulating resin) is then filled into the gap.

As the adherend, various substrates such as lead frames and circuitboards (such as wiring circuit boards) can be used. The material of thesubstrates is not particularly restricted and there may be mentionedceramic substrates and plastic substrates. Examples of the plasticsubstrates include epoxy substrates, bismaleimide triazine substrates,and polyimide substrates.

In the flip chip bonding, the material of the bump and the conductivematerial is not particularly restricted and examples thereof includesolders (alloys) such as tin-lead-based metal materials,tin-silver-based metal materials, tin-silver-copper-based metalmaterials, tin-zinc-based metal materials, and tin-zinc-bismuth-basedmetal materials, and gold-based metal materials and copper-based metalmaterials.

Incidentally, in the present step, the conductive material is melted toconnect the bump at the circuit face side of the semiconductor chip 5and the conductive material on the surface of the adherend 6. Thetemperature at the melting of the conductive material is usually about260° C. (e.g., 250° C. to 300° C.). The dicing tape-integrated film forsemiconductor back surface of the invention can be made to have thermalresistance capable of enduring the high temperature in the flip chipbonding step by forming the film for semiconductor back surface with anepoxy resin or the like.

Moreover, the washing liquid to be used at washing the opposing face(electrode-formed face) and the gap between the semiconductor chip 5 andthe adherend 6 in the flip chip bonding is not particularly restrictedand the liquid may be an organic washing liquid or may be an aqueouswashing liquid. The film for semiconductor back surface in the dicingtape-integrated film for semiconductor back surface of the invention hassolvent resistance against the washing liquid and has substantially nosolubility to these washing liquid. Therefore, as mentioned above,various washing liquids can be employed as the washing liquid and thewashing can be achieved by any conventional method without requiring anyspecial washing liquid.

In the invention, the encapsulating material to be used at theencapsulation of the gap between the semiconductor chip 5 and theadherend 6 is not particularly restricted as long as the material is aresin having an insulating property (an insulating resin) and may besuitably selected and used among known encapsulating materials such asencapsulating resins. The encapsulating resin is preferably aninsulating resin having elasticity. Examples of the encapsulating resininclude resin compositions containing an epoxy resin. As the epoxyresin, there may be mentioned the epoxy resins exemplified in the above.Furthermore, the encapsulating resin composed of the resin compositioncontaining an epoxy resin may contain a thermosetting resin other thanan epoxy resin (such as a phenol resin) or a thermoplastic resin, inaddition to the epoxy resin. Incidentally, a phenol resin can beutilized as a curing agent for the epoxy resin and, as such a phenolresin, there may be mentioned phenol resins exemplified in the above.

In the encapsulation step with the encapsulating resin, theencapsulating resin is usually cured by heating to achieveencapsulation. The curing of the encapsulating resin is usually carriedout at 175° C. for 60 to 90 seconds in many cases. However, in theinvention, without limitation thereto, the curing may be performed at atemperature of 165 to 185° C. for several minutes, for example. In thecase that the film for semiconductor back surface (wafer adhesion layerand/or laser marking layer) is formed of a resin composition containinga thermosetting resin, the thermosetting resin constituting the film forsemiconductor back surface can be completely or almost completely curedat the curing of the encapsulating resin.

Incidentally, the distance of the gap between the semiconductor chip 5and the adherend 6 is generally from about 30 to about 300 μm.

In the semiconductor device (flip chip-mounted semiconductor device)produced using the dicing tape-integrated film for semiconductor backsurface according to the invention, since the film for semiconductorback surface including the wafer adhesion layer having a specificelastic modulus and the laser marking layer having a specific elasticmodulus is attached on the back surface of the chip-shaped workpiece ina form that the laser marking layer becomes the outermost face, lasermarking can be applied with excellent visibility. Particularly, thelaser marking can be applied with an excellent contrast ratio and thusit is possible to observe various kinds of information (literalinformation, graphical information, etc.) applied by the laser markingwith a good visibility. At the laser marking, a known laser markingapparatus can be utilized. Moreover, as the laser, it is possible toutilize various lasers such as a gas laser, a solid-state laser, and aliquid laser. Specifically, as the gas laser, any known gas lasers canbe utilized without particular limitation but a carbon dioxide laser(CO₂ laser) and an excimer laser (ArF laser, KrF laser, XeCI laser, XeFlaser, etc.) are suitable. As the solid-state laser, any knownsolid-state lasers can be utilized without particular limitation but aYAG laser (such as Nd:YAG laser) and a YVO₄ laser are suitable.

Since the flip chip-mounted semiconductor device produced using thedicing tape-integrated film for semiconductor back surface of theinvention is a semiconductor device mounted by the flip chip mountingmethod, the device has a thinned and miniaturized shape as compared witha semiconductor device mounted by a die-bonding mounting method. Thus,the flip chip-mounted semiconductor devices can be suitably employed asvarious electronic devices and electronic parts or materials and membersthereof. Specifically, as the electronic devices in which the flipchip-mounted semiconductor devices of the invention are utilized, theremay be mentioned so-called “mobile phones” and “PHS”, small-sizedcomputers [e.g., so-called “PDA” (handheld terminals), so-called“notebook-sized personal computer”, so-called “Net Book (trademark)”,and so-called “wearable computers”, etc.], small-sized electronicdevices having a form where a “mobile phone” and a computer areintegrated, so-called “Digital Camera (trademark)”, so-called “digitalvideo cameras”, small-sized television sets, small-sized game machines,small-sized digital audio players, so-called “electronic notepads”,so-called “electronic dictionary”, electronic device terminals forso-called “electronic books”, mobile electronic devices (portableelectronic devices) such as small-sized digital type watches, and thelike. Needless to say, electronic devices (stationary type ones, etc.)other than mobile ones, e.g., so-called “desktop personal computers”,thin type television sets, electronic devices for recording andreproduction (hard disk recorders, DVD players, etc.), projectors,micromachines, and the like may be also mentioned. In addition,electronic parts or materials and members for electronic devices andelectronic parts are not particularly restricted and examples thereofinclude parts for so-called “CPU” and members for various memory devices(so-called “memories”, hard disks, etc.).

EXAMPLES

The following will illustratively describe preferred examples of theinvention in detail. However, the materials, the blending amount, andthe like described in these examples are not intended to limit the scopeof the invention to only those unless otherwise stated, and they aremerely explanatory examples. Moreover, part in each example is a weightstandard unless otherwise stated.

Production Example 1

21 parts of an epoxy resin (a trade name “EPICOAT 1004” manufactured byJER Co., Ltd.), 22 parts of a phenol resin (a trade name “MILEX XLC-4L”manufactured by Mitsui Chemicals, Inc.), 77 parts of sphere silica (atrade name “SO-25R” manufactured by Admatechs Co., Ltd., averageparticle diameter: 0.5 μm), 4 parts of a dye 1 (a trade name “OIL GREEN502” manufactured by Orient Chemical Industries Co., Ltd.), and 4 partsof a dye 2 (a trade name “OIL BLACK BS” manufactured by Orient ChemicalIndustries Co., Ltd.) based on 100 parts of an acrylic acid ester-basedpolymer (a trade name “PARACRON W-197CM” manufactured by Negami ChemicalIndustrial Co., Ltd.) having ethyl acrylate and methyl methacrylate asmain components were dissolved into methyl ethyl ketone to prepare aresin composition solution having a solid concentration of 23.6% byweight (sometimes referred to as “resin composition solution A”).

Production Example 2

113 parts of an epoxy resin (a trade name “EPICOAT 1004” manufactured byJER Co., Ltd.), 121 parts of a phenol resin (a trade name “MILEX XLC-4L”manufactured by Mitsui Chemicals, Inc.), 246 parts of sphere silica (atrade name “SO-25R” manufactured by Admatechs Co., Ltd., averageparticle diameter: 0.5 μm), 5 parts of a dye 1 (a trade name “OIL GREEN502” manufactured by Orient Chemical Industries Co., Ltd.), and 5 partsof a dye 2 (a trade name “OIL BLACK BS” manufactured by Orient ChemicalIndustries Co., Ltd.) based on 100 parts of an acrylic acid ester-basedpolymer (a trade name “PARACRON W-197CM” manufactured by Negami ChemicalIndustrial Co., Ltd.) having ethyl acrylate and methyl methacrylate asmain components were dissolved into methyl ethyl ketone to prepare aresin composition solution having a solid concentration of 23.6% byweight (sometimes referred to as “resin composition solution B”).

(Evaluation of Adhesiveness to Wafer)

With regard to the resin layers derived from the resin compositionsolution A and the resin composition solution B prepared in ProductionExamples 1 and 2, an adhesive force to a wafer was measured by thefollowing measuring method of the adhesive force and it is evaluatedwhether each resin layer has a suitable adhesive force as a waferadhesion layer or not according to the following evaluation standard foradhesiveness The results of the evaluation or measurement are shown inTable 1.

<Measuring Method of Adhesive Force>

A polyethylene terephthalate film (thickness: 38 μm; sometimes referredto as a “PET film”) was attached to one surface of each of the resinlayers derived from the resin composition solution A and the resincomposition solution B prepared in Production Examples 1 and 2 to obtaina resin layer-attached PET film. A silicon wafer (thickness: 0.6 mm) asa wafer was placed on a hot plate, and the film was attached thereon ata prescribed temperature (50° C.) by reciprocating a roller of 2 kg oncein a form that the resin layer of the resin layer-attached PET filmcomes into contact with the wafer. Thereafter, the laminate was allowedto stand on a hot plate (50° C.) for 2 minutes and then allowed to standat ordinary temperature (about 23° C.) for 20 minutes. After standing,the resin layer-attached PET film was peeled (peeled at an interfacebetween the resin layer and the wafer) at a temperature of 23° C. underconditions of a peel angle of 180° and a tensile rate of 300 mm/min byusing a peel tester (a trade name “AUTOGRAPH AGS-J” manufactured byShimadzu Corporation). A maximum load of the loads at the peeling time(a maximum value of the loads from which a peak top at the beginning ofmeasurement has been eliminated) was measured, and an adhesive force(N/10 mm-width) of the resin was determined while regarding this maximumload as an adhesive force between the resin layer and the wafer(adhesive force of the resin layer to the wafer).

(Evaluation Standard for Adhesiveness)

Good: Adhesive force to the wafer was 1 N/10 mm-width or more;Poor: Adhesive force to the wafer was less than 1 N/10 mm-width.

In the measuring method of adhesive force, the resin layer wasreinforced with a PET film but a similar value of the adhesive force isobtained even when a pressure-sensitive adhesive tape (a trade name“BT315” manufactured by Nitto Denko Corporation) is used instead of thePET film.

TABLE 1 Production Example Adhesive force 1 Good 2 Poor

From Table 1, the resin layer derived from the resin compositionsolution A of Production Example 1 has a good adhesive force to thewafer and thus is suitable as a wafer adhesion layer. Therefore, theresin layer can be utilized as a wafer adhesion layer. On the otherhand, the resin layer derived from the resin composition solution B ofProduction Example 2 has a low adhesive force to the wafer and thus isnot suitable as a wafer adhesion layer. Therefore, the resin layercannot be utilized as a wafer adhesion layer.

<Evaluating Method for Laser Marking Property>

With regard to the resin layers derived from the resin compositionsolution A and the resin composition solution B prepared in ProductionExamples 1 and 2, a laser marking property was evaluated or measured bythe following evaluating or measuring method of the laser processabilityand it is evaluated whether the resin layer has a suitable laser markingproperty as a laser marking layer or not according to the followingevaluation standard for laser processability. The results of theevaluation or measurement are shown in Table 2.

<Evaluation and Measurement Method for Laser Processability>

Each of the resin layers derived from the resin composition solution Aand the resin composition solution B prepared in Production Examples 1and 2 was irradiated with a laser [wavelength: 532 nm, a lasergeneration apparatus (a trade name “MD-S9900” manufactured by KeyenceCorporation)] under a condition of an intensity of 1.0 W and processeddepth processed by the laser irradiation was measured with a lasermicroscope.

(Evaluation Standard for Laser Processability)

Good: Laser processed depth was 2 μm or more;Poor: Laser processed depth was less than 2 μm.

TABLE 2 Production Example Laser processability 1 Poor 2 Good

From Table 2, the resin layer derived from the resin compositionsolution B of Production Example 2 has a good laser processability andthus is suitable as a laser marking layer. Therefore, the resin layercan be utilized as a laser marking layer. On the other hand, the resinlayer derived from the resin composition solution A of ProductionExample 1 has a low laser processability and thus is not suitable as alaser marking layer. Therefore, the resin layer cannot be utilized as alaser marking layer.

(Measurement of Elastic Modulus)

With regard to the resin layers derived from the resin compositionsolution A and the resin composition solution B manufactured inProduction Examples 1 and 2, the elastic modulus was measured by thefollowing measuring method of elastic modulus. The results of themeasurement are shown in Table 3,

<Measuring Method of Elastic Modulus>

The elastic modulus of each of the resin layers derived from the resincomposition solution A and the resin composition solution B manufacturedin Production Examples 1 and 2 was measured by manufacturing each of theresin layers derived from the resin composition solution A and the resincomposition solution B and measuring the elastic modulus in a tensilemode under conditions of a sample width of 10 mm, a sample length of22.5 mm, a sample thickness of 0.2 mm, a frequency of 1 Hz, and atemperature elevating rate of 10° C./minute under a nitrogen atmosphereat a prescribed temperature (50° C.) using a dynamic viscoelasticitymeasuring apparatus “Solid Analyzer RS A2” manufactured by RheometricsCo. Ltd. and the measured elastic modulus is regarded as a value oftensile storage elastic modulus E′ obtained.

TABLE 3 Production Example Elastic modulus 1  7 MPa 2 150 MPa

(Measurement of Physical Properties)

With respect to each of the resin layers derived from the resincomposition solution A and the resin composition solution B prepared inProduction Examples 1 and 2, visible light transmittance (%), a moistureabsorbance (% by weight) and a weight decrease ratio (% by weight) weremeasured, respectively in the following manners. The results of themeasurement are shown in the following Table 4.

Measuring Method of Visible Light Transmittance>

Each of the resin layers derived from the resin composition solution Aand the resin composition solution B prepared in Production Examples 1and 2 was irradiated with visible light using “ABSORPTION SPECTRAPHOTOMETER” (a trade name, manufactured by Shimadzu Corporation). Awavelength of the visible light was regulated to from 400 nm to 800 nm.A light intensity of the visible light which had transmitted through thefilm for semiconductor back surface by this irradiation was measured andcalculated according to the following expression.

Visible light transmittance (%)=[(Light intensity of visible light aftertransmitting through the resin layer)/(Initial light intensity ofvisible light)]×100

<Measuring Method of Moisture Absorbance>

Each of the resin layers derived from the resin composition solution Aand the resin composition solution B prepared in Production Examples 1and 2 was allowed to stand in a constant-temperature andconstant-humidity chamber at a temperature of 85° C. and a humidity of85% RH for 168 hours. A weight before and after standing was measured,and a moisture absorbance (% by weight) was calculated according to thefollowing expression.

Moisture absorbance (% by weight)=[{(Weight after allowing the resinlayer to stand)−(Weight before allowing the resin layer tostand)}/(Weight before allowing the resin layer to stand)]×100

<Measuring Method of Weight Decrease Ratio>

Each of the resin layers derived from the resin composition solution Aand the resin composition solution B prepared in Production Examples 1and 2 was allowed to stand in a drying machine at a temperature of 250°C. for 1 hour. A weight before and after standing was measured, and aweight decrease ratio (% by weight) was calculated according to thefollowing expression.

Weight decrease ratio (% by weight)=[{(Weight before allowing the resinlayer to stand)−(Weight after allowing the resin layer tostand)}/(Weight before allowing the resin layer to stand)]×100

TABLE 4 Moisture Weight decrease Visible light absorbance ratiotransmittance (%) (% by weight) (% by weight) Production 1% or less 0.51.2 Example 1 Production 1% or less 0.3 0.9 Example 2

Example 1 Manufacture of Film for Semiconductor Back Surface

The resin composition solution A prepared in Production Example 1 wasapplied onto a releasably treated film as a release liner (separator)composed of a polyethylene terephthalate film having a thickness of 50μm, which had been subjected to a silicone-releasing treatment, and thendried at 130° C. for 2 minutes to form a wafer-side resin layer (waferadhesion layer) having a thickness (average thickness) of 10 μm.Thereafter, the resin composition solution B prepared in ProductionExample 2 was applied onto the wafer-side resin layer (wafer adhesionlayer) and then dried at 130° C. for 2 minutes to form an outer resinlayer (laser marking layer) having a thickness (average thickness) of 10μm, thereby manufacturing a film for semiconductor back surface(sometimes referred to as “film A for semiconductor back surface”)having a thickness (average thickness) of 20 μm.

<Manufacture of Dicing Tape-Integrated Film for Semiconductor BackSurface>

The above film A for semiconductor back surface was attached onto thepressure-sensitive adhesive layer of a dicing tape (a trade name “V-8-T”manufactured by Nitto Denko Corporation; average thickness of basematerial: 65 μm, average thickness of pressure sensitive adhesive layer:10 μm) using a hand roller in a form that the outer resin layer comesinto contact with the pressure-sensitive adhesive layer of the dicingtape, to manufacture a dicing tape-integrated film for semiconductorback surface.

Comparative Example 1 Manufacture of Film for Semiconductor Back Surface

The resin composition solution B prepared in Production Example 2 wasapplied onto a releasably treated film as a release liner (separator)composed of a polyethylene terephthalate film having a thickness of 50μm, which had been subjected to a silicone-releasing treatment, and thendried at 130° C. for 2 minutes to form a wafer-side resin layer (waferadhesion layer) having a thickness (average thickness) of 10 μm.Thereafter, the resin composition solution A prepared in ProductionExample 1 was applied onto the wafer-side resin layer (wafer adhesionlayer) and then dried at 130° C. for 2 minutes to form an outer resinlayer (laser marking layer) having a thickness (average thickness) of 10μm, thereby manufacturing a film for semiconductor back surface(sometimes referred to as “film B for semiconductor back surface”)having a thickness (average thickness) of 20 μm.

<Manufacture of Dicing Tape-Integrated Film for Semiconductor BackSurface>

The above film B for semiconductor back surface was attached on thepressure-sensitive adhesive layer of a dicing tape (a trade name “V-8-T”manufactured by Nitto Denko Corporation; average thickness of basematerial: 65 μm, average thickness of pressure-sensitive adhesive layer:10 μm) using a hand roller in a form that the outer resin layer comesinto contact with the pressure-sensitive adhesive layer of the dicingtape, to manufacture a dicing tape-integrated film for semiconductorback surface.

Comparative Example 2 Manufacture of Film for Semiconductor Back Surface

The resin composition solution A prepared in Production Example 1 wasapplied onto a releasably treated film as a release liner (separator)composed of a polyethylene terephthalate film having a thickness of 50μm, which had been subjected to a silicone-releasing treatment, and thendried at 130° C. for 2 minutes to form a resin layer having a thickness(average thickness) of 20 μm, thereby manufacturing a film forsemiconductor back surface (sometimes referred to as “film C forsemiconductor back surface”) having a thickness (average thickness) of20 μm. Therefore, the film C for semiconductor back surface has aconstitution of a single layer. That is, the film for semiconductor backsurface having a single layer constitution (i.e., the resin layer)serves as a wafer side resin layer and also as an outer resin layer.

<Manufacture of Dicing Tape-Integrated Film for Semiconductor BackSurface>

The above film C for semiconductor back surface was attached on thepressure-sensitive adhesive layer of a dicing tape (a trade name “V-8-T”manufactured by Nitto Denko Corporation; average thickness of basematerial: 65 μm, average thickness of pressure-sensitive adhesive layer:10 μm) using a hand roller to manufacture a dicing tape-integrated filmfor semiconductor back surface.

Comparative Example 3 Manufacture of Film for Semiconductor Back Surface

The resin composition solution B prepared in Production Example 2 wasapplied onto a releasably treated film as a release liner (separator)composed of a polyethylene terephthalate film having a thickness of 50μm, which had been subjected to a silicone-releasing treatment, and thendried at 130° C. for 2 minutes to form a resin layer having a thickness(average thickness) of 20 μm, thereby manufacturing a film forsemiconductor back surface (sometimes referred to as “film D forsemiconductor back surface”) having a thickness (average thickness) of20 μm. Therefore, the film D for semiconductor back surface has aconstitution of a single layer. That is, the film for semiconductor backsurface having a single layer constitution (i.e., the resin layer)serves as a wafer side resin layer and also as an outer resin layer.

<Manufacture of Dicing Tape-Integrated Film for Semiconductor BackSurface>

The above film D for semiconductor back surface was attached on thepressure-sensitive adhesive layer of a dicing tape (a trade name “V-8-T”manufactured by Nitto Denko Corporation; average thickness of basematerial: 65 μm, average thickness of pressure-sensitive adhesive layer:10 μm) using a hand roller to manufacture a dicing tape-integrated filmfor semiconductor back surface.

Incidentally, in the dicing tape-integrated film for semiconductor backsurfaces according to Example 1, the thickness (average thickness) ofthe film for semiconductor back surface is 20 μm. Moreover, with regardto the dicing tapes (a trade name “V-8-T” manufactured by Nitto DenkoCorporation), the thickness (average thickness) of the base material is65 μm, the thickness (average thickness) of the pressure-sensitiveadhesive layer is 10 μm, and the total thickness is 75 μm. Therefore, inthe dicing tape-integrated film for semiconductor back surfacesaccording to Example 1, the ratio of the thickness of the film forsemiconductor back surface to the thickness of the pressure-sensitiveadhesive layer of the dicing tape (thickness of the film forsemiconductor back surface/thickness of the pressure-sensitive adhesivelayer of the dicing tape; ratio in average thickness) is 20/10 and theratio of the thickness of the film for semiconductor back surface to thethickness of the dicing tape (total thickness of the base material andthe pressure-sensitive adhesive layer) (thickness of the film forsemiconductor back surface/thickness of the dicing tape; ratio inaverage thickness) is 20/75.

(Evaluation)

With regard to the dicing tape-integrated film for semiconductor backsurfaces manufactured in Example 1 and Comparative Examples 1 to 3, adicing property, a picking-up property, a flip chip bonding property, amarking property of the wafer back surface, and an appearance propertyof the wafer back surface were evaluated or measured by the followingevaluating or measuring method. The results of the evaluation ormeasurement are shown in Table 5.

<Evaluating Method of Dicing Property/Picking-Up Property>

Using each dicing tape-integrated film for semiconductor back surface ofExample 1 and Comparative Examples 1 to 3, the dicing property wasevaluated by actually dicing a semiconductor wafer and then peelingability was evaluated, thus dicing performance or picking-up performanceof the dicing tape-integrated film for semiconductor back surface beingevaluated.

A semiconductor wafer (diameter: 8 inches, thickness: 0.6 mm; a siliconmirror wafer) was subjected to a back surface polishing treatment and amirror wafer having a thickness of 0.2 mm was used as a workpiece. Afterthe separator was peeled from the dicing tape-integrated film forsemiconductor back surface, the mirror wafer (workpiece) was attachedonto the film for semiconductor back surface (i.e., onto the wafer-sideresin layer of the film for semiconductor back surface) by rollerpress-bonding at 70° C. and dicing was further performed. Herein, thedicing was performed as full cut so as to be a chip size of 10 mmsquare. In this regard, conditions for semiconductor wafer grinding,attaching conditions, and dicing conditions are as follows.

(Conditions for Semiconductor Wafer Grinding)

Grinding apparatus: a trade name “IDG-8560” manufactured by DISCOCorporationSemiconductor wafer: 8 inch diameter (back surface was ground so as tobe until a thickness of 0.2 mm from a thickness of 0.6 mm)

(Attaching Conditions)

Attaching apparatus: a trade name “MA-3000III” manufactured by NittoSeiki Co., Ltd.Attaching speed: 10 mm/minAttaching pressure: 0.15 MPaStage temperature at the time of attaching: 70° C.

(Dicing Conditions)

Dicing apparatus: a trade name “DFD-6361” manufactured by DISCOCorporationDicing ring: “2-8-1” (manufactured by DISCO Corporation)Dicing speed: 30 mm/secDicing blade:

Z1; “203O-SE 27HCDD” manufactured by DISCO Corporation

Z2; “203O-SE 27HCBB” manufactured by DISCO Corporation

Dicing blade rotation speed:

Z1; 40,000 r/min

Z2; 45,000 r/min

Cutting method: step cuttingWafer chip size: 10.0 mm square

In the dicing, it was confirmed whether the mirror wafer (workpiece) wasfirmly held on the dicing tape-integrated film for semiconductor backsurface without peeling to effect the dicing satisfactory or not. Thecase where the dicing was well performed was ranked “Good” and the casewhere the dicing was not well performed was ranked “Poor”, thus thedicing ability being evaluated.

Next, the chip-shaped workpieces obtained by dicing were peeled from thepressure-sensitive adhesive layer of the dicing tape together with thefilm for semiconductor back surface by pushing up the workpieces fromthe dicing tape side of the dicing tape-integrated film forsemiconductor back surface with a needle, whereby the chip-shapedworkpieces in a state where the back surface had been protected with thefilm for semiconductor back surface were picked up. The picking-up ratio(%) of the chips (400 pieces in total) on this occasion was determinedto evaluate the picking-up property. Therefor; the picking-up propertyis better when the picking-up ratio is closer to 100%.

Here, the picking-up conditions are as follows.

(Picking-Up Conditions for Semiconductor Wafer)

Picking-up apparatus: a trade name “SPA-300” manufactured by ShinkawaCo., Ltd.Number of picking-up needles: 9 needlesPushing-up speed of needle: 20 mm/sPushing-up distance of needle: 500 μmPicking-up time: 1 secondDicing tape-expanding amount: 3 mm

<Evaluation Method for Flip Chip Bonding Property>

On the chip-shaped workpiece according to each Example or ComparativeExample obtained by the above-mentioned <Evaluating method of dicingproperties/picking-up property> using the dicing tape-integrated filmfor semiconductor back surface according to each Example or ComparativeExample, a bump formed at the circuit face of the chip-shaped workpiecewas brought into contact with a conductive material (solder) forconjunction attached to a connecting pad of the circuit board in a formwhere the surface (circuit face) of the chip-shaped workpiece wasopposed to the surface of the circuit board possessing a wiringcorresponding to the circuit face, and the conductive material wasmelted under pressure by raising the temperature to 260° C. and thencooled to room temperature, whereby the chip-shaped workpiece was fixedto the circuit board to manufacture a semiconductor device. The flipchip bonding property on this occasion was evaluated according to thefollowing evaluation standard.

(Evaluation Standard for Flip Chip Bonding Property)

Good: Mounting could be achieved by the flip chip bonding method with notrouble;Poor: Mounting could not be achieved by the flip chip bonding method.

<Evaluating Method for Marking Property of Wafer Back Surface>

Laser marking was applied with YAG laser on the back surface of thechip-shaped workpiece (i.e., surface of the outermost layer of the filmfor semiconductor back surface) in the semiconductor device obtained bythe above-mentioned

<Evaluating Method for Flip Chip Bonding Property>. On the informationobtained by the laser marking (bar-code information), the markingproperty (laser marking property) of the semiconductor device obtainedusing the dicing tape-integrated film for semiconductor back surfaceaccording to each Example or Comparative Example was evaluated accordingto the following evaluation standard.

(Evaluation Standard for Marking Property)

Good: The number of persons who judged the information obtained by thelaser marking satisfactorily visible was 8 persons or more amongrandomly selected 10 adult persons;Poor: The number of persons who judged the information obtained by thelaser marking satisfactorily visible was 7 persons or less amongrandomly selected 10 adult persons.

<Evaluation Method for Appearance Property of Wafer Back Surface>

On the chip-shaped workpiece according to each Example and ComparativeExample obtained by the above-mentioned <Evaluating method of dicingproperty/picking-up property> using the dicing tape-integrated film forsemiconductor back surface according to each Example and ComparativeExample, the appearance property of the back surface of the chip-shapedworkpiece was visually evaluated according to the following evaluationstandard.

(Evaluation Standard for Appearance Property>

Good: No peeling (lifting) was observed between the back surface of thewafer (silicon wafer) and the film for semiconductor back surface in thechip-shaped workpiece;Poor: Peeling (lifting) was observed between the back surface of thewafer (silicon wafer) and the film for semiconductor back surface in thechip-shaped workpiece.

TABLE 5 Wafer- Picking- opposite up Flip chip Wafer-side side resinDicing property bonding Marking Appearance resin layer layer property(%) property property property Example 1 Production Production Good 100Good Good Good Example 1 Example 2 Comparative Production ProductionGood 100 Good Poor Good Example 1 Example 2 Example 1 ComparativeProduction Production Good 100 Good Poor Good Example 2 Example 1Example 1 Comparative Production Production Good 100 Good Good PoorExample 3 Example 2 Example 2 Note) In each of the dicingtape-integrated films for semiconductor back surface according toComparative Examples 2 and 3, the film for semiconductor back surfacehad a single layer constitution.

From Table 5, it was confirmed that the dicing tape-integrated film forsemiconductor back surface according to Example 1 possessed a functionas a dicing tape and a function as a film for semiconductor back surface(such as close adhesiveness to a wafer and laser marking property) atexcellent levels.

Since a dicing tape and a film for semiconductor back surface are formedin an integrated fashion in the dicing tape-integrated film forsemiconductor back surface according to the invention as well as thefilm for semiconductor back surface includes a wafer adhesion layerhaving an elastic modulus (at 50° C.) of 10 MPa or less and a lasermarking layer having an elastic modulus (at 50° C.) of 100 MPa or more,the dicing tape-integrated film for semiconductor back surface can beutilized from the dicing step of a semiconductor wafer to the flip chipbonding step of a semiconductor chip. Namely, the dicing tape-integratedfilm for semiconductor back surface according to the invention can besuitably used as a dicing tape-integrated film for semiconductor backsurface possessing both functions of a dicing tape and a film forsemiconductor back surface at the production of semiconductor devices bya flip chip bonding method.

While the present invention has been described in detail and withreference to specific embodiments thereof, it will be apparent to oneskilled in the art that various changes and modifications can be madetherein without departing from the scope thereof.

This application is based on Japanese patent application No. 2009-292768filed Dec. 24, 2009 and Japanese patent application No. 2010-253084filed Nov. 11, 2010, the entire contents thereof being herebyincorporated by reference.

1. A film for flip chip type semiconductor back surface, which is to beformed on a back surface of a semiconductor element flip-chip connectedon an adherend, wherein said film comprises a wafer adhesion layer and alaser marking layer, and wherein the wafer adhesion layer has an elasticmodulus (at 50° C.) of 10 MPa or less and the laser marking layer has anelastic modulus (at 50° C.) of 100 MPa or more.
 2. The film for flipchip type semiconductor back surface according to claim 1, wherein thewafer adhesion layer and the laser marking layer are both colored.
 3. Adicing tape-integrated film for semiconductor back surface, comprising:a dicing tape comprising a base material and a pressure-sensitiveadhesive layer formed on the base material; and the film for flip chiptype semiconductor back surface according to claim 1, which is formed onthe pressure-sensitive adhesive layer of the dicing tape in such amanner that the laser marking layer is laminated on thepressure-sensitive adhesive layer of the dicing tape.
 4. The dicingtape-integrated film for semiconductor back surface according to claim3, which is used for a flip chip-mounted semiconductor device.
 5. Aprocess for producing a semiconductor device, the process comprising:attaching a workpiece onto a wafer adhesion layer in the film for flipchip type semiconductor back surface of the dicing tape-integrated filmfor semiconductor back surface according to claim 3, dicing theworkpiece to form a chip-shaped workpiece, peeling the chip-shapedworkpiece from the pressure-sensitive adhesive layer of the dicing tapetogether with the film for flip chip type semiconductor back surface,and fixing the chip-shaped workpiece to an adherend by flip chipbonding.
 6. A flip chip-mounted semiconductor device, which ismanufactured using the dicing tape-integrated film for semiconductorback surface according to claim 3, the semiconductor device comprising achip-shaped workpiece and the film for flip chip type semiconductor backsurface attached to a back surface of the chip-shaped workpiece.